SWR2 – Coronal Mass Ejections, Shock Waves and Energetic Particles
Talks
SWR2.1 Mon 4/11 14:00-16:00, room Auditorium
Author(s): Erika Palmerio
Predictive Science Inc.
Abstract: The environment shaped by the Sun—the heliosphere—is extremely dynamic, with its structure being constantly shaped and altered by the solar activity on multiple time scales. Aside from changes that take place over longer intervals (such as the 11-year cycle), the large-scale structure of the heliosphere is affected by energetic transient events—solar eruptions. The loss of equilibrium of magnetic structures rooted on the Sun can result in a plethora of interconnected phenomena such as the release of solar flares, the liftoff of coronal mass ejections (CMEs), the formation of shock waves, and the acceleration of solar energetic particles (SEPs). As structures resulting from solar eruptions move away from the Sun, they interact with and affect the overall heliosphere as well as the magnetic environments of planets and other solar system bodies. Over the past years, the research community has been gradually shifting its main focus from the Sun–Earth chain to the Sun–heliosphere–planets interconnected system, thus taking advantage of multi-spacecraft and multi-point observations as well as modelling to build a comprehensive, holistic picture of how a given event influences different heliospheric regions and environments.
In this presentation, we will first provide a review of the advantages of multi-spacecraft observations of solar eruptive events and how they have helped us build the overall picture of CME structure and evolution as well as SEP acceleration and transport that forms our current understanding. We will then showcase examples of detailed studies, both in the observational and modelling regimes, that have been made possible due to the availability of multi-point measurements. These will include events observed remotely and/or in situ by the latest generation of heliophysics missions, i.e. Parker Solar Probe and Solar Orbiter, but also by planetary missions that carry instrumentation relevant to heliophysics such as MAVEN, BepiColombo, and JUICE. Finally, we will speculate on possible future avenues that are worthy of exploring to reach a deeper understanding of CMEs and SEPs from their eruption and acceleration throughout their heliospheric journey, especially in terms of novel space missions that may improve not only our knowledge from a fundamental physics standpoint, but also our prediction and forecasting capabilities.
Author(s): Stefaan Poedts, Senne Doumen, Anwesha Maharana, Peter Wintoft, Tinatin Baratashvili
KU Leuven; KU Leuven; KU Leuven; Swedish Institute of Space Physics, Lund, Sweden; KU Leuven
Abstract: The EUropean Heliospheric FORecasting Information Asset (EUHFORIA, Pomoell and Poedts, 2018), a physics-based and data-driven heliospheric and CME propagation model can predict the solar wind plasma and magnetic field conditions at Earth. It contains several flux-rope CME models, such as the simple spheromak models and the more advanced FRi3D and toroidal CME models. This enables the prediction of the sign and strength of the magnetic field components upon the arrival of the CME at Earth and, thus, the geo-effectiveness of the CME impact. EUHFORIA has been coupled to several global magnetosphere models like OpenGGCM, GUMICS-4, and Gorgon-Space. In addition, the synthetic data at L1 (from the EUHFORIA simulation) can be used as input for empirical models and neural networks to predict the geomagnetic indices like Disturbance-storm-time (Dst) or Kp that quantify the impact of the magnetized plasma encounters on Earth’s magnetosphere. Hence, we also coupled EUHFORIA to empirical models (Obrien and McPherron, 2000b, and Newell et al, 2006) and machine learning (NARMAX, and the models from Wintoft et al. (2017 and 2021)) based models to predict the geomagnetic indices. We then compare the results of these models to observational data to evaluate their performance in predicting the geo-effect indices. To quantify these comparisons, we use the advanced dynamic time warping method. Since we use synthetic data from the EUHFORIA simulations, we can obtain the input parameters for running the geomagnetic indices models two to three days in advance, unlike the 60-90 minutes lead time of the real-time measurements.
We perform ensemble modelling considering the L1 monitor precision in its orbit as well as the uncertainty in the initial CME parameters (longitude and latitude) at launch, for error quantification. This is done by evaluating the geomagnetic index models using synthetic data from the virtual satellites around L1 in EUHFORIA’s simulation domain. In addition, we also investigate the impact of the spatio-temporal resolution of EUHFORIA output in forecasting the geomagnetic indices, exploiting the adaptive mesh refinement feature in ICARUS (Baratashvili et al., 2022). Overall, this study validates various space weather forecasting model chains and checks the best compatibility and predictive capabilities using EUHFORIA data for operational space weather forecasting.
Author(s): David Barnes, Erika Palmerio, Tanja Amerstorfer, Eleanna Asvestari, Luke Barnard, Maike Bauer, Jaša Čalogović, Phillip Hess, Christina Kay, Kenny Kenny
RAL Space, UK; Predictive Science Inc., USA; Geosphere Austria, Austria; University of Helsinki, Finland; University of Reading, UK; Geosphere Austria, Austria; Hvar Observatory, Croatia; U.S. Naval Research Laboratory, USA; NASA Goddard Space Flight Center, USA; University of Colorado Boulder, USA
Abstract: Forecasting the arrival of Coronal Mass Ejections at Earth depends on accurate characterisation of their three-dimensional structure and kinematics. This is usually achieved via forward-modelling; by applying an assumed model of the CME structure to white-light coronagraph observations, which may be achieved using just a small number of observing spacecraft. An alternative approach is inverse modelling, whereby white light images are treated as two-dimensional projections of the Thomson-scattered light from the 3D plasma distribution. Inversion of these images, taken from multiple vantage points, is purely mathematical and allows the full three-dimensional CME density structure to be constrained. However, the method requires multiple observing spacecraft and so, to-date, it has only been successfully applied to CMEs when it is augmented with other methods, such as forward modelling.
With the continued operation of SOHO and STEREO-A, as well as the launches of Solar Orbiter and Parker Solar Probe, multi-spacecraft CME studies are now commonplace. Furthermore, upcoming missions such as Vigil, SWFO-L1 and proposals to reach polar and L4 orbits mean that it is a most opportune time to investigate the potential of multi-spacecraft remote-sensing observations with respect to CME analysis. Consequently, we propose to establish the effectiveness of the tomographic inversion method and we achieve this by means of synthetic imagery. We create the synthetic images by employing state-of-the-art magnetohydrodynamic (MHD) simulations of the solar corona using the CORonal HELiospheric (CORHEL) model. This is performed for a fleet of spacecraft, such that various combinations can be combined and used to perform tomography on the synthetic imagery, with the goal of establishing the minimum requirements for successful 3D CME reconstruction. We demonstrate how the number of observing spacecraft influences the solution, how well the technique is augmented using polarised brightness measurements and the optimal orbital configuration, including out-of-ecliptic observers.
This work is supported by the International Space Science Institute (ISSI) in Bern, Switzerland, as part of ISSI International Team project #587.
Author(s): Emma Davies, Christian Möstl, Eva Weiler, Hannah Rüdisser, Ute Amerstorfer, Timothy Horbury, Helen O’Brien, Edward Fauchon-Jones, Jean Morris
Austrian Space Weather Office, GeoSphere Austria; Austrian Space Weather Office, GeoSphere Austria; Austrian Space Weather Office, GeoSphere Austria; Austrian Space Weather Office, GeoSphere Austria; Austrian Space Weather Office, GeoSphere Austria; Department of Physics, Imperial College London; Department of Physics, Imperial College London; Department of Physics, Imperial College London; Department of Physics, Imperial College London
Abstract: Coronal mass ejections (CMEs) are the main drivers of severe space weather at Earth which can affect both satellite and ground systems, necessitating accurate predictions for timely mitigation. The complicated nature of the processes affecting CMEs as they propagate makes understanding and predicting their physical properties and global structure a challenging task, from both a fundamental and practical space weather perspective. Current challenges lie in forecasting CME arrival time and magnetic structure prior to Earth arrival, critical for assessing geo-effectiveness and closely tied to our ability to measure their magnetic field configuration between the Sun and 1 AU.
Recent opportunities provided by Solar Orbiter crossing the Sun-Earth line have allowed us to monitor upstream solar wind conditions in real-time. On 23 March 2024, Solar Orbiter observed a fast and Earth directed CME, at 0.39 AU from the Sun and 9 degrees in heliospheric longitude away from Earth. It provided observations of the CME magnetic field vector in real time, with a lead time of over one day before Earth impact. We present the analysis we performed that led to the first real-time prediction of the geomagnetic magnitude of a severe geomagnetic storm (minimum Dst -130 nT) with sufficient accuracy and lead time. Such a scenario has allowed us to demonstrate the necessity of future upstream solar wind monitors towards accurate and timely predictions of space weather effects.
Author(s): Enno Müller, Volker Bothmer, Manuela Temmer, Jackie Davies, Iulia Chifu, Greta Cappello
Institute for Astrophysics and Geophysics, Georg-August-University Goettingen, Germany; Institute of Astrophysics and Geophysics, Georg-August-University Goettingen, Germany; Institute of Physics, University of Graz, Austria; STFC RAL Space, Rutherford Appleton Laboratory, Harwell Campus, Oxfordshire OX11 0QX, UK; Institute for Astrophysics and Geophysics, Georg-August-University Goettingen, Germany; Institute of Physics, University of Graz, Austria
Abstract: Coronal Mass Ejections (CMEs) are pivotal drivers of space weather, influencing satellite operations, communication systems, and posing significant risks. Space weather forecasting from SOHO at the L1 vantage point is limited due to its halo perspective on earthward-directed CMEs, often leading to misinterpretations and inaccuracies in CME arrival time predictions. We analyzed 45 CME events from 2007-2014, utilizing multi-viewpoint observations from SOHO and STEREO A and B satellites across increasing separation angles from 20 to 165 degrees. Our study classified these events based on their characteristics observed at the Sun, using coronagraph imagery, their propagation through the interplanetary medium, using heliospheric imager data, and their in-situ signatures at Earth. We employed 3D geometric modeling and a modified drag-based propagation model to predict arrival times, subsequently interpreting the results within the context of existing error estimates. Our findings reveal critical physical processes affecting CME arrival time predictions. By identifying and analyzing these processes, we highlight the potential for significant improvements in space weather forecasting. These insights are crucial for optimizing the predictive capabilities of the European Space Agency’s (ESA) upcoming L5 mission, Vigil, thereby mitigating the adverse effects of space weather on Earth.
Author(s): Clementina Sasso, Federico Landini, Giuliana Russano, Frédéric Auchere, David Berghmans, Johann Hirzberger, Phil Hess, David Orozco Suárez, Luciano Rodriguez, Hanna Strecker, Gherardo Valori, Angelos Vourlidas
INAF-Astronomical Observatory of Capodimonte, Napoli, Italy; INAF-Astrophysical Observatory of Torino, Torino, Italy; INAF-Astronomical Observatory of Capodimonte, Napoli, Italy; Institut d’Astrophysique Spatiale, CNRS and Université Paris-Saclay, Orsay, France; Solar-Terrestrial Centre of Excellence – SIDC, Royal Observatory of Belgium, Brussels; Max Planck for Solar System Research, Göttingen, Germany; U.S. Naval Research Laboratory (NRL), Washington D.C., USA; Instituto de Astrofísica de Andalucía (IAA-CSIC), Granada, Spain; Solar-Terrestrial Centre of Excellence – SIDC, Royal Observatory of Belgium, Brussels; Instituto de Astrofísica de Andalucía (IAA-CSIC), Granada, Spain; Max Planck for Solar System Research, Göttingen, Germany; The Johns Hopkins University Applied Physics Laboratory, Laurel, USA
Abstract: During the Remote Science Windows, Solar Orbiter observations are organized into Solar Orbiter Observing Plans (SOOPs), where a SOOP is a set of common operations from multiple instruments addressing several mission sub-objectives. The Eruption Watch SOOP is a full-disk, high resolution plan, designed to catch eruptive events. All remote sensing instruments are involved while in-situ payload provides continuous observations. Up to now, we have had nine Eruption Watch campaigns.
In this presentation, we concentrate on the analysis of some eruptive events, observed in particular during two of these campaigns that happened in April and October 2023. We selected two events observed by PHI, EUI, Metis (in both the VL and UV channel), and SolOHI, so to investigate their physical and dynamical properties from the photosphere to the extended corona.
Moreover, we selected also an event observed at a high temporal cadence (1 minute) by the Metis coronagraph in both channels where we can clearly follow the CME’s front moving rapidly in the VL images, and then the prominence, which, unlike the front, is also visible in the UV images because it is colder than the front.
Finally, having observations starting from 2022 we make also a statistical analysis on the observed events.
SWR2.2 Tue 5/11 09:00-10:15, room Auditorium
Author(s): Marco Pinto, Beatriz Sanchez-Caño, Laura Rodriguez-García, António Pessanha Gomes, Francisca Ferreira Santos, Rami Vainio, Go Murakami, Olivier Witasse, Patrícia Goncalves, Emilia Kilpua, Wojtek Hajdas, André Galli, Arto Lehtolainen, Daniel Heyner, Philipp Oleynik, Manuel Grande, Johannes Benkhoff
European Space Agency; University of Leicester; European Space Agency; LIP; LIP; University of Turku; Japanese Aerospace Exploration Agency; European Space Agency; LIP; University of Helsinki; Paul Scherrer Institute; University of Bern; University of Helsinki; TU Braunschweig; University of Turku; Aberystwyth University; European Space Agency
Abstract: Solar Energetic Particles (SEPs) originate in the Sun, primarily during solar flare events and coronal mass ejections (CMEs). These high energy particles, composed mainly of protons, electrons, and heavier ions, pose significant risks to spacecraft and human space exploration. Understanding the properties, propagation, and impact of SEPs is crucial for advancing space weather prediction and mitigating associated risks. While a large effort has been made to model SEP events, most observations have been done by near Earth and/or Earth-orbiting missions. More recently, with the launch of Parker Solar Probe and Solar Orbiter, a larger observational space is covered using multi-mission data. However, the location of these missions is not always ideal. Planetary missions, often equipped with instruments capable of measuring high energy particles, offer additional observation points.
The European Space Agency’s BepiColombo and JUICE missions are currently traveling to their respective destinations, Mercury and the Jovian system. BepiColombo’s 7-year journey (2018-2025) and JUICE’s 8-year journey (2023-2031) offer exceptional opportunities for multi-mission scientific investigations. While BepiColombo tours the inner Solar System, JUICE will delve deep into the outer system paster Mars orbit after 2027 providing a unique observation of SEPs far from the Sun. Additionally, BepiColombo and JUICE can serve as upstream solar wind monitors for planets like Venus or Mars when in opposition.
Both missions carry dedicated radiation monitors, the Bepicolombo Environment Radiation Monitor (BERM), and the RADiation hard Electron Monitor (RADEM), operated continuously through the cruise and nominal mission phases. BepiColombo also operates its suite of instruments dedicated to plasma and solar physics including the Solar Intensity X-Ray and Particle Spectrometer (SIXS), the Solar Particle Monitor (SPM); and BepiColombo Planetary Magnetometer (MPO-MAG), the regularly during the cruise phase.
This work reports on SEP observations detected by both missions, including interplanetary magnetic field measurements from BepiColombo. These observations during the cruise phases provide invaluable data that aid the planetary and heliophysics communities in characterizing Space Weather within the inner Solar System. Additionally, we will explore the correlation between SEP event and radiation effects in both missions, in particular Single Event Upsets.
Author(s): Nariaki Nitta, Meng Jin, Gang Li, Christina Cohen, Ruizhu Chen, J. Todd Hoeksema, Nina Dresing
Lockheed Martin Advanced Technology Center; Lockheed Martin Advanced Technology Center; General Linear Space Plasma Lab LLC; California Institute of Technology; Stanford University; Stanford University; University of Turku
Abstract: It is widely accepted that the onset of solar energetic particle (SEP) events is governed by when the observer gets connected to a shock wave. Observations are generally not inconsistent with this picture. But we still do not clearly understand rather basic questions regarding SEPs and shocks. For example, even though we know of many SEP events that were observed at widely separate longitudes, thanks to multi-spacecraft coverage, simple parameters that characterize CMEs may not directly correlate with how far from the source region and how quickly particles are detected. Moreover, we still do not know how to characterize the magnitude of the shock wave from observations that may be essential for particle acceleration. Other problems we should not ignore may include possible effects on SEP properties of the interaction of the CME with other CMEs and large-scale heliospheric structures, and the origin of energetic electrons in gradual SEP events. We discuss how improved modeling efforts may give us clues to these questions. In particular, we show how state-of-the-art MHD models such as AWSoM can provide important information of how shock waves develop temporally and spatially and when their magnetic connection to the observer is established, in the context of some wide spread SEP events archived by Richardson et al. (2014) and Richardson (2024).
Author(s): Abdullah Shmies, Maher Dayeh, Radoslav Bucik, Samuel Hart
The University of Texas at San Antonio; Southwest Research Institute; Southwest Research Institute; The University of Texas at San Antonio
Abstract: The exact origins and acceleration mechanisms governing solar energetic particle (SEP) events remain an open question in heliophysics. SEP production is thought to be dominated by two main mechanisms: (i) flare-associated acceleration via magnetic reconnection processes and (ii) shock-accelerated processes in association with fast coronal mass ejections (CMEs). In extreme cases, SEP events can produce a significant increase in the number of high-energy particles (10s – 100s of MeV), posing significant radiation threats to space assets. Because these extreme events are associated with bright (M- & X-class) solar flares and high-speed CMEs, the production of high-energy particles likely arises from the interplay between flare and shock-accelerated processes. Understanding the role each source plays in SEP production can significantly improve our predictive capabilities to mitigate the effects of space weather.
In this study, we perform statistical analysis on a large set of extreme SEP events listed in NOAA’s GOES list. The list comprises 130 SEP events including 18 Ground Level Events (GLEs) and 4 sub-GLEs recorded between 1997 and 2017. Among these, we identify SEP events with available high-energy fluxes suitable for timing analysis. Using a velocity dispersion analysis approach, we determine each event’s solar particle release (SPR) time and compare it to the onset of the parent X-ray flare. By correlating the time difference between the flare and particle release with the spectral properties and abundance ratios of both protons and heavy ions, we assess the contribution of flares to the production of SEPs in these extreme events.
Author(s): Nina Dresing, Immanuel Jebaraj, Nicolas Wijsen, Erika Palmerio, Manon Jarry, Eleanna Asvestari, Christina Cohen, Grant Mitchell, Christina Lee, Wenwen Wei, Athanasios Kouloumvakos, Jan Gieseler, Christian Palmroos, Laura Rodriguez-Garcia
University of Turku, Finland; University of Turku, Finland; KU Leuven, Belgium; Pred. Science Inc., San Diego, US; IRAP, CNRS, France; University of Helsinki, Finland; Caltech, Pasadena, US; NASA GSFC, US; Space Sciences Lab, UC Berkeley, US; Space Sciences Lab, UC Berkeley, US; The Johns Hopkins University Applied Physics Laboratory, US; University of Turku, Finland; University of Turku, Finland; ESA, ESAC, Spain
Abstract: On 13 March 2023, when the Parker Solar Probe (PSP) mission was situated on the far side of the Sun as seen from Earth, a large solar eruption took place, which created a strong solar energetic particle (SEP) event observed by multiple spacecraft all around the Sun.
At five locations in the inner heliosphere, that is PSP, Solar Orbiter, BepiColombo, STEREO A, and near-Earth spacecraft, an energetic event was observed, and even MAVEN at Mars detected the SEP event. Clear signatures of an in-situ shock and a related energetic storm particle (ESP) event were present also at the far-side observers Solar Orbiter, BepiColombo, STEREO A, and near-Earth spacecraft, suggesting that the interplanetary CME-driven shock extended all around the Sun. However, the solar event was accompanied by a series of CMEs. We use EUHFORIA simulations and investigate the role of these multiple CMEs in versus a circumsolar blast-wave scenario in explaining the observations.
Author(s): George C. Ho, Athanasios Kouloumvakos, Glenn M. Mason, Robert C. Allen, Robert F. Wimmer-Schweingruber, Javier Rodríguez-Pacheco, Raúl Gómez-Herrero
Southwest Research Institute; Johns Hopkins Applied Physics Laboratory; Johns Hopkins Applied Physics Laboratory; Southwest Research Institute; University of Kiel; University of Alcalá; University of Alcalá
Abstract: Solar Orbiter was launched in February 2020 during the ascending phase of Solar Cycle #25 with increase activities of solar flares, coronal mass ejections (CMEs) and solar energetic particles (SEPs). Understanding the physical processes operating in Solar Energetic Particle (SEP) events is a major goal of the Solar Orbitermission because of the importance of acceleration processes in solar system and astrophysical sites, and because of the potential impact of these events on space hardware.
Within a two-week period from May 2-15, 2024, a prolific active region (AR 13663) produced 12 X-class and 88 M-class flares, 14 high-energy (>10 MeV) SEP events, and at least 18 CMEs when it could be directly observed from space assets at the Earth vantage point. Being on the far side of the Sun, Solar Orbiter was able continue observations of this AR as it rotated into the Solar Orbiter field-of-view on May 15, 2024 and continued to produce several more X-class flares, SEP events, and CMEs. We report here energetic particle data from ACE, STEREO-A, and Solar Orbiter that were all well positioned to measure the SEP increases associated with this AR. We find that the majority of the flares did not produce any SEPs, but one SEP event was detected by both ACE and Solar Orbiter despite being separated in longitude by 190°. We also compare this series of SEP events with all large SEPs that have been reported so far in Solar Cycle #25, as well as with SEP fluxes measured in the previous two solar cycles.
SWR2.3 Wed 6/11 09:00-10:15, room Auditorium
Author(s): Helen Norman, Ravindra Desai, Tony Arber
University of Warwick; University of Warwick; University of Warwick
Abstract: Galactic cosmic rays (GCRs) are charged particles with extremely high energies originating from outside the heliosphere. Their passage through the solar wind is affected by many long and short term factors, including transient structures such as coronal mass ejections (CMEs). The short term decrease in GCR flux caused by CMEs, and observed by charged particle detectors on spacecraft and ground-based neutron monitors is called a Forbush decrease (FD). FDs have a varied and complex profile, often showing a 2-step decrease corresponding to the structure of the CME – the first decrease corresponding to the shock and turbulent sheath region, and the second caused by reduced radial transport into the magnetic cloud structure. Current analytic and numerical models of this phenomenon have considered diffusion through the shock or into the magnetic cloud as separate processes, but have not been applied to realistic, 3-dimensional CME field geometries. We present progress in combining magnetohydrodynamic simulations of CMEs and background solar wind with full-orbit test particle simulations to reproduce the entirety of a 2-step FD and recovery. This will allow us to investigate the transport processes responsible and gain a greater understanding of how energetic particle observations can be used to infer the global structure of CMEs.
Author(s): Pietro Zucca
ASTRON – Netherlands institute for Radio Astrnomy
Abstract: The role of radio observations in understanding Coronal Mass Ejections (CMEs), shock waves, and energetic particles is pivotal, particularly at low frequencies. Instruments like the Low-Frequency Array (LOFAR) offer significant advantages in this domain. LOFAR operates in the 10-240 MHz range, providing unprecedented sensitivity and resolution for observing the solar corona and related phenomena. By utilizing advanced imaging techniques and digital beam-forming, LOFAR can rapidly repoint and simultaneously observe multiple sky regions, making it an agile tool for solar studies.
Radio observations at low frequencies are particularly effective in locating and analyzing the fine structures of type II radio bursts, which are indicative of shock waves propagating through the solar corona. These bursts, often associated with CMEs, can be studied in detail using LOFAR’s high-resolution imaging capabilities. The ability to capture dynamic spectra and imaging locations combined with state of the art modelling of the characteristics of the ambient medium, allows for the detailed scenario where radio waves are produced in the context of the solar corona’s magnetic field and plasma conditions.
We use LOFAR radio data and advanced models of the corona, such as electron density, Alfven speed, magnetic field, and magnetic field topology, to understand the shock signatures, the CMEs, and the locations where particles are accelerated. This comprehensive approach, combining observational data with advanced modeling, underscores the importance of low-frequency radio telescopes in solar physics research.
In the talk, recent results on a series of studies using LOFAR are presented. The studies highlight the effectiveness of radio observations in advancing our understanding of CMEs, shock waves, and regions where particles are accelerated.
Author(s): Diana Morosan, Nina Dresing, Immanuel Jebaraj, Christian Palmroos, Jan Gieseler, Peijin Zhang, Pietro Zucca, Jens Pomoell, Emilia Kilpua, Sanna Normo, Rami Vainio
University of Turku; University of Turku; University of Turku; University of Turku; University of Turku; New Jersey Institute of Technology; ASTRON; University of Helsinki; University of Helsinki; University of Turku; University of Turku
Abstract: Energetic particles in the heliosphere are produced by flaring processes on the Sun or by shocks driven by coronal mass ejections. These particles can be detected remotely through the electromagnetic radiation they generate (X-rays or radio emission) or in situ by spacecraft monitoring the Sun and the heliosphere. Here, we investigate the acceleration location, escape, and propagation directions of electron beams producing radio bursts observed with the Low Frequency Array (LOFAR) and compare them to hard X-ray (HXR) emission and in situ electrons observed at Solar Orbiter. These observations are combined with a three-dimensional (3D) representation of the electron acceleration locations and results from a magneto-hydrodynamic (MHD) model of the solar corona in order to investigate the origin and connectivity to Solar Orbiter and relate the electrons observed remotely at the Sun to in situ electrons. We observed a long-duration metric-decametric type II radio burst with good connectivity to Solar Orbiter, which also observed a significant electron event. However, type III radio bursts and hard X-rays (HXR) were also observed but likely connected to Solar Orbiter by different far-sided field lines. The injections times of the in situ electrons at low and high energies are simultaneous with the onset of the type II radio burst, while the onset of the group of type III bursts and the presence of HXR peaks occurs a few minutes earlier.
Author(s): Edin Husidic, Nicolas Wijsen, Luis Linan, Michaela Brchnelova, Rami Vainio, Stefaan Poedts
KU Leuven, Belgium & University of Turku, Finland; KU Leuven, Belgium; KU Leuven, Belgium; KU Leuven, Belgium; University of Turku, Finland; KU Leuven, Belgium & University of Maria Curie-Skłodowska, Poland
Abstract: Coronal mass ejections (CMEs) are the primary drivers of space weather, capable of causing significant disruptions to Earth’s magnetic field and ground-based technology when directed towards Earth. Additionally, fast CME-driven shock waves serve as powerful particle accelerators, enabling solar energetic particles (SEPs) to reach energies of hundreds of MeV/nucleon, posing serious threats to astronauts and satellites. Numerical models such as PARADISE (PArticle Radiation Asset Directed at Interplanetary Space Exploration), which uses inputs from the magnetohydrodynamic (MHD) simulation models EUHFORIA (EUropean Heliospheric FORecasting Information Asset) and Icarus, simulate the acceleration and transport of SEPs in the inner heliosphere beyond radial distances of 0.1 au, helping our physical understanding of these phenomena and serving as forecasting tools.
To extend our studies to radial distances below 0.1 au and address the evolution of CMEs as well as the acceleration and transport of energetic particles in the corona, we introduce the novel COCONUT+PARADISE model. The COCONUT (COolfluid COroNa UnsTructured) code, part of the COOLFLuiD (Computational Object-Oriented Libraries for FLuid Dynamics) platform, is a data-driven, global, three-dimensional (3D) coronal MHD model. Using synoptic maps for the inner boundary conditions, COCONUT solves the full set of 3D ideal MHD equations on an unstructured grid from 1 to 25 solar radii. For the modelling of CMEs within COCONUT simulations, we employ the unstable modified Titov-Demoulin flux rope model. PARADISE then utilises the coronal configurations from COCONUT to propagate energetic particles as test particles through these backgrounds by solving the focused transport equation (FTE) in a stochastic manner. We present simulation results that demonstrate the behaviour of energetic particles within the corona, and highlight the potential of our model for future studies of particle transport and acceleration from the solar surface up to 1 au and beyond.
SWR2.4 Thu 7/11 09:00-10:15, room Auditorium
Author(s): Federica Chiappetta, Silvia Perri, Giuseppe Nisticò, Francesco Pucci, Francesco Malara, Luca Sorriso-Valvo, Gaetano Zimbardo
Dipartimento di Fisica, Università della Calabria, Rende, Italy; Dipartimento di Fisica, Università della Calabria, Rende, Italy; Dipartimento di Fisica, Università della Calabria, Rende, Italy; CNR, Institute for Plasma Science and Technology (ISTP), Bari, Italy; Dipartimento di Fisica, Università della Calabria, Rende, Italy; CNR, Institute for Plasma Science and Technology (ISTP), Bari, Italy – KTH, Division of Space and Plasma Physics, Stockholm, Sweden; Dipartimento di Fisica, Università della Calabria, Rende, Italy
Abstract: Solar Energetic Particles (SEPs) represent a natural hazard for the Earth environment, from the instruments on board spacecraft to the electricity networks and astronauts life. These events are produced by solar eruptions such as flares and Coronal Mass Ejections (CMEs) that spread into the interplanetary space. In this study, we analyze energetic particle fluxes at CME-driven shocks measured in-situ by multiple satellites at different radial distance and longitudes, and derive the parameters of the shocks such as the compression ratio, the angle between the magnetic field and the normal to the shock, and the Mach numbers. When it is possible, we compare these quantities with the shock parameters computed at the coronal sources using remote-sensing observations. The energy spectra measured at the selected interplanetary shocks will be modeled and fitted in order to infer ongoing acceleration processes. Magnetic field turbulence is also investigated by calculating the power spectral density, the autocorrelation function, in order to derive the turbulence correlation length, and the level of magnetic intermittency, putting these properties in relation with particle energy spectra. This study is achieved in the context of the research project “Data-based predictions of solar energetic particle arrival to the Earth” funded by the Italian Ministry of Research under the grant scheme PRIN-2022-PNRR.
Author(s): Jens Pomoell, Ranadeep Sarkar, Stephan G. Heinemann, Eleanna Asvestari
University of Helsinki; University of Helsinki; University of Helsinki; University of Helsinki
Abstract: Magnetohydrodynamic modeling of the large-scale plasma dynamics caused by space-weather relevant Coronal Mass Ejections (CMEs) is conventionally carried out employing either a coronal or heliospheric approach. In the former, the complex dynamics from the low corona to the heliosphere is modeled, while in the latter the simulation is started at heliocentric distances at which the solar wind is characterized by super-Alfvénic outflow. In contrast, we have developed an alternative to this paradigm, wherein the middle corona is included in the model, encompasses a spatial domain starting at ~ 5 solar radii and extending out to the heliosphere. Including the sub-Alfvénic middle corona presents several challenges distinct from the standard paradigm, while also providing unique opportunities for exploiting available observations for more accurate data-constrained modeling of magnetized CMEs. In this work, we showcase our novel approach and the performance of the model using multi-spacecraft observations for several events.
Author(s): Marius Echim, Daria Shukhobodskaia, Luciano Rodriguez, Andrei Zhukov, Fabio Bacchini, Harikrishnan Aravindakshan, Costel Munteanu, Gabriel Voitcu, Eliza Teodorescu
Royal Belgian Institute for Space Aeronomy; Royal Observatory of Belgium, Brussels, Belgium; Royal Observatory of Belgium, Brussels, Belgium; Royal Observatory of Belgium, Brussels, Belgium; Royal Belgian Institute for Space Aeronomy; Departement Wiskunde, KU Leuven, Belgium; Institute of Space Science, Romania; Institute of Space Science, Romania; Institute of Space Science, Romania
Abstract: We investigate the effects on planetary plasma turbulence of two CMEs impacting Venus, Earth and Mars. The first CME erupts on 14th of January 2009 and has properties suggesting a NWS flux rope. The ICME impacts Venus on January 17th and the Earth on January 18th, respectively; it misses Mars. No shock is observed from in-situ data. The second CME erupts on 5th of March 2018, at 23:39 UT; a shock is detected by DSCOVR and ACE around 17:20 UT on 9th of March. The flux rope is inclined with respect to the ecliptic, with a rotation of the magnetic field components in a mostly SWN direction at Earth. The ICME misses Venus but arrives at the Earth on 9th of March and at Mars on 10th of March; the signatures at Mars do not fully confirm direct impact. We use in-situ measurements of magnetic field in the magnetosheaths of Venus, Earth and Mars to investigate the spectral and statistical properties of turbulent fluctuations prior and after the ICME impact. We use data provided by Venus Express, Cluster and MAVEN on which we apply a full set of analysis methods, including computation of the Power Spectral Density (PSD), the Probability Density Functions (PDFs) and the flatness. We find that:
Venus – Earth event: the structure of Venus magnetosheath turbulence is distorted by the arrival of the ICME. Indeed, no signature of an inertial range could be identified post ICME impact, although is detected prior to the impact. The ICME seems less effective for the Earth magnetosheath where a pre-existing inertial range “survives” the arrival of the ICME, with some instabilities developing post impact. While the magnetic fluctuations in the pristine solar wind and the magnetic cloud show clear signatures of intermittency, the fluctuations detected in Venus magnetosheath have a tendency to become more Gaussian post ICME impact; however, the situation is reversed for the Earth magnetosheath, where the magnetic fluctuations show a tendency to become non- Gaussian virtually at all scales, post ICME impact.
Earth – Mars event: The PSD computed for solar wind magnetic field inside the ICME magnetic cloud (probed in-situ by MAVEN) shows signatures of developing instabilities. Prior to the ICME impact the turbulence state of the Mars magnetosheath is rather disordered, no clear inertial range can be identified. Post impact, an inertial range of scales is observed. Magnetic fluctuations are rather Gaussian in the pristine solar wind but show non-Gaussian features during ICME. Intermittency increases in the Mars magnetosheath post ICME impact.
Author(s): Gabriel D. Muro
California Institute of Technology
Abstract: During mid-May 2024, active region (AR) 13664 produced a series of M- and X-class flares along with several coronal mass ejections (CMEs) which resulted in exceptionally strong aurora at low latitudes on Earth. This study will present in-situ solar energetic particle (SEP) data from STEREO-A and Parker Solar Probe (PSP) as their connectivity to AR 13664 varied throughout the superstorm period.
SWR2.5 Thu 7/11 14:15-15:15, room Auditorium
Author(s): Hisashi Hayakawa, Sergey Koldobskiy, Alexandar Mishev, Stepan Poluianov, Agnieszka Gil, Ilya Usoskin
University of Nagoya, Japan; University of Oulu, Finland; University of Oulu, Finland; University of Oulu, Finland; University of Siedlce, Poland; University of Oulu, Finland
Abstract: Solar eruptive events can produce solar energetic particles (SEPs) which occasionally be detected by ground-based neutron monitors (NMs) as ground-level enhancements (GLEs). The strongest GLE occurred on 23 February 1956 (conventionally numbered GLE #5) and had the hardest known SEP spectrum, providing a benchmark reference for related studies. However, it was previously analyzed using data from different, often secondary sources. Here we revisited the analyses of this event based on the original contemporary records. We have collected, digitised and verified the source records for NM measurements during GLE #5 based on contemporaneous publications and unpublished archives of the University of Chicago. Using the revised datasets and full modelling, we revised the reconstruction of the energy spectra and angular characteristics of SEPs for GLE #5, resulting in a slightly softer, but still agreeing within the uncertainties of the recent studies, SEP spectral estimate. The SEP flux was found to be highly anisotropic in the early phase of the event. This provides a revised reference basis for further analyses and modelling of strong and extreme SEP events and their terrestrial impacts.
Author(s): Artem Epifanov, Kamen Kozarev
Institute of Astronomy, Bulgarian Academy of Sciences; Institute of Astronomy, Bulgarian Academy of Sciences
Abstract: The source population of particles is a crucial yet very poorly constrained parameter in global solar energetic particle simulations. This is due to the lack of in situ measurements close to the Sun, where the suprathermal particle populations have not yet been modified by acceleration and transport effects in the interplanetary environment of the heliosphere. The two main identified populations of SEP particle sources are ambient coronal suprathermals and suprathermals impulsively pre-accelerated in flares. In this work, we investigate the former. We have employed quiet-time in situ suprathermal ion measurements by the Parker Solar Probe, taken during its fourth solar perihelion encounter (Jan-Feb 2020), as inner boundary input source populations for an SEP global transport simulation with the EPREM model with a solar wind description given by a MAS heliospheric model simulation. We compare the EPREM results to in situ measurements near 1 AU in order to optimize the model transport parameters. The goal is to investigate how quiet-time suprathermal ion populations are modified in a realistic heliospheric environment during a relatively quiet period, and to assess the applicability of such a diagnostic approach in near-real time space weather forecasting simulations.
14:45 Observations of Energetic Neutral Atoms in the 2022 February 15 Solar Energetic Particle Event
Author(s): C.M.S. Cohen, R.A. Leske, O.C. St. Cyr, G.M. Mason
Caltech; Caltech; GSFC (retired); JHUAPL
Abstract: Although energetic neutral atoms (ENAs) are expected to be produced near the Sun during large solar energetic particle (SEP) events, their detection by SEP instruments near 1 AU has been very limited. They were observed by the SEP instrument on the Solar Terrestrial Relations Observatory (STEREO) during 2006 December 5 SEP event, while evidence of ENAs has been found through reanalysis of observations by the Solar Anomalous and Magnetospheric Particle Explorer obtained near the equator in low Earth orbit and associated with several large X-ray flares and fast coronal mass ejections (CMEs). Recent examination of data from the STEREO Low Energy Telescope (LET) during the large 2022 February 15 SEP event has resulted in another detection of ENAs at 1 AU. The timing and spectrum of the ENAs combined with the location of the source region (behind the solar east limb from STEREO’s viewpoint) suggests that these ENAs are most likely a result of acceleration by a CME-driven shock when the CME was at approximately 2–3 RS rather than originating from postflare loops.
Author(s): Stefan Purkhart, Astrid Veronig, Bernhard Kliem, Robert Jarolim, Karin Dissauer, Ewan Dickson, Tatiana podladchikova, Säm Krucker
University of Graz, Austria; University of Graz, Austria; University of Potsdam, Germany; High Altitude Observatory, USA; NorthWest Research Associates, USA; University of Graz, Austria; Skolkovo Institute of Science and Technology, Russia; University of Applied Sciences and Arts Northwestern Switzerland
Abstract: The strongest space weather effects are driven by flares accompanied by a coronal mass ejection (CME), so-called eruptive flares. However, confined flares may be an important step to form flux ropes that eventually lead to an eruption in the form of a CME. Here we present a multi-point study of the formation of a filament, its rapid restructuring during a confined C2 flare, and its eruption about 1.5 hours later associated with a fast halo CME and a M4 flare. We take advantage of the quasi-quadrature position (84°) between SDO and Solar Orbiter during its first science perihelion, by combining close-up (0.33 AU) observations of the event on the solar limb from the Solar Orbiter/STIX and EUI instruments with on-disk observations from SDO/AIA and HMI, along with nonlinear force-free field (NLFFF) extrapolations.
During the confined C2 flare, the filament’s southern half disappeared, and the remaining plasma flowed into a new, longer channel, similar to an EUV hot channel seen during the flare. Our analysis suggests that loop-loop reconnection occurred in an essentially vertical current sheet at a polarity inversion line below the breakup region and involved field lines surrounding the filament channel. This scenario is supported by concentrated currents and free magnetic energy built up by antiparallel flows. It can explain the extended flare loop arcade, the EUV hot channel, and the filament restructuring as the reconnection progressed to involve the filament itself. In addition, it provides a general mechanism for the formation of the long filament channel via tether cutting, which was active throughout the filament’s continuous rise phase, beginning at least 30 min before the C2 flare and continuing until the eruption. These results demonstrate how rapid changes in a filament’s topology can be driven by a confined flare due to loop-loop reconnection, and how this can contribute to a prolonged tether-cutting process leading to a full eruption.
Posters
Posters II Display Thu 7/11 – Fri 8/11, room C1A – Aeminium
Authors in attendance: Thu 7/11 10:15–11:30, 15:15-16:15; Fri 8/11 10:15–11:30
Author(s): Shantanu Jain, Tatiana Podladchikova, Galina Chikunova, Karin Dissauer, Astrid M. Veronig
Skolkovo Institute of Science and Technology, Moscow, Russia; Skolkovo Institute of Science and Technology, Moscow, Russia; Hvar Observatory, University of Zagreb, Croatia; Skolkovo Institute of Science and Technology, Moscow, Russia; Northwest Research Associates, Boulder, USA; University of Graz, Kanzelhöhe Observatory for Solar and Environmental Research, Kanzelhöhe 19, 9521 Treffen, Austria
Abstract: Coronal mass ejections (CMEs) are solar eruptions of plasma and magnetic fields that significantly impact Space Weather, causing disruptions in technological systems and potential damage to power grids when directed towards Earth. Traditional coronagraphs face challenges in accurately measuring the early evolution of Earth-directed CMEs due to projection effects. Coronal dimmings, characterized by localized reductions in extreme-ultraviolet (EUV) and soft X-ray emissions, serve as crucial indicators of CMEs in the low corona. These dimmings arise from mass loss and expansion during the eruption. This research introduces a novel approach, DIRECD (Dimming InfeRred Estimate of CME Direction), for estimating the initial direction of coronal mass ejections (CMEs) by analyzing the expansion of coronal dimmings. The approach involves 3D simulations of CMEs using a geometric cone model, exploring parameters like width, height, source location, and deflection from the radial direction. The dominant direction of dimming evolution is then determined, and an inverse problem is solved to reconstruct an ensemble of CME cones at various heights, widths, and deflections. The 3D CME direction is determined by comparing the CME projections onto the solar sphere with the dimming geometry and extent. This methodology is demonstrated on two well-documented CME events that occurred on October 1, 2011, and September 6, 2011. The results reveal initial propagation directions of CMEs that closely align with those obtained from 3D observations of the CME bubble in the EUV low corona and from GCS 3D modeling of the white-light CME in the higher corona. Furthermore, these findings are consistent with multi-viewpoint coronagraph observations of the CMEs from both the SOHO and STEREO spacecraft. The research highlights the potential of coronal dimming data for early estimation of CME direction.
Author(s): Manuela Temmer, Mateja Dumbovic, Karmen Martinic, Greta M. Cappello, Akshay K. Remeshan, Daniel Milosic, Filip Matkovic, Florian Koller, Jasa Calogovic
Institute of Physics, University of Graz, Austria; Hvar Observatory, Faculty of Geodesy, University of Zagreb, Croatia; Hvar Observatory, Faculty of Geodesy, University of Zagreb, Croatia; Institute of Physics, University of Graz, Austria; Hvar Observatory, Faculty of Geodesy, University of Zagreb; Institute of Physics, University of Graz, Austria; Hvar Observatory, Faculty of Geodesy, University of Zagreb; Institute of Physics, University of Graz, Austria; Hvar Observatory, Faculty of Geodesy, University of Zagreb
Abstract: Solar cycle 25 is close to its expected peak and related activity is at a high. Recently, many complex events were observed remotely and measured in-situ. Some of them even caused aurorae in low latitudes, repeatedly confirming that the interaction between multiple CMEs, as well as CIRs, lead to extreme conditions in near-Earth space. For the enhanced solar activity period at the end of 2023, we study a set of “homologous” events on the Sun. Several CMEs interacted and additionally interfered by a high-speed stream from a coronal hole. The two sets of events involve the same active regions and coronal hole but are separated by a full solar rotation. We point out the complexity for each set of events and aim to understand how the geomagnetic effects, differ such to cause stable-red-arc aurorae in southern Europe for events from one rotation but not for those from the next rotation.
Author(s): José Juan González Avilés, Pete Riley, Michal Ben-Nun, Ozzy Rigoberto Orozco Plascencia
Escuela Nacional de Estudios Superiores, Unidad Morelia, Universidad Nacional Autónoma de México; Predictive Science Inc.; Predictive Science Inc.; Universidad Michoacana de San Nicolás de Hidalgo
Abstract: Coronal mass ejections (CMEs) drive geomagnetic storms that could impact Earth’s magnetic environment. Therefore, to describe their properties upstream of the Earth requires developing sophisticated numerical models. In this study, we apply sunRunner3D (SR3D), a new global MHD model for initiating and following the evolution of CMEs from the outer corona to about 1 AU. We employ the hydrodynamic cone model and a more sophisticated toroidal magnetic field configuration to inject the CMEs as time-dependent boundary conditions at r=30 Rs and describe their propagation through the inner heliosphere. Notably, we demonstrate how SR3D can interpret the signatures of CMEs observed by heliospheric spacecraft, including Earth-based missions (WIND, ACE), Parker Solar Probe, and Solar Orbiter. Although SR3D currently supports a modest range of options and features, with community adoption, it could become a valuable tool for space weather applications.
Author(s): Karmen Martinić, Eleanna Asvestari, Mateja Dumbović, Tobias Rindlisbacher, Manuela Temmer, Bojan Vršnak
University of Zagreb, Faculty of Geodesy, Hvar Observatory; Faculty of Science, Department of Physics, University of Helsinki; University of Zagreb, Faculty of Geodesy, Hvar Observatory; Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern; Institute of Physics, University of Graz; Hvar Observatory, Faculty of Geodesy, University of Zagreb
Abstract: Coronal mass ejections (CMEs) are complex magnetized plasma structures in which the magnetic field spirals around a central axis forming a so-called flux rope (FR). The central FR axis can be oriented at any angle with respect to the ecliptic, defining the FR’s inclination. During its journey, a CME propagates through the interplanetary magnetic field and the solar wind, both of which are neither homogeneous nor isotropic. Consequently, CMEs with different orientations encounter different conditions of the surrounding medium. The interaction of a CME with its environment thus depends, among other things, on the FR’s inclination. This study aims to understand the effects of inclination on CME propagation. We have performed simulations using the EUHFORIA 3D magnetohydrodynamics model. This study focuses on two CMEs modeled as spheromaks with almost identical properties, differing only in their inclination. We show the effects of CME orientation on sheath evolution, MHD drag, and non-radial flows by analyzing simulation data from a swarm of 81 virtual spacecraft distributed across the inner heliosphere. We found that the sheath duration increases with radial distance from the Sun and that the increase is larger at the flanks of the CME. Non-radial flows within the studied sheath region appear larger outside the ecliptic plane, indicating a ”sliding” of the IMF out-of ecliptic plane. We found that the calculated drag parameter does not remain constant with radial distance and that the hypothesized inclination dependence of the drag parameter cannot be resolved with our numerical setup.
Author(s): Sanna Normo, Diana Morosan, Rami Vainio, Peijin Zhang, Pietro Zucca
University of Turku; University of Turku; University of Turku; New Jersey Institute of Technology; ASTRON
Abstract: Type II solar radio bursts are regarded as signatures of shock-accelerated electrons in the solar corona. They show emission lanes drifting slowly from higher to lower frequencies at the fundamental and/or harmonic of the local plasma frequency. Occasionally, these lanes can be further split into two components. This phenomenon is known as band-splitting, and its origin is still under debate. In this study, we investigate the band-splitting of a type II radio burst with the Low Frequency Array (LOFAR). The type II burst exhibits a fundamental and a harmonic emission lane. Both lanes are further split into a higher-frequency and a lower-frequency band. The type II burst is associated with a very faint CME, and the occurrence of a type II burst and herringbone bursts superimposed on the type II indicate the presence of a coronal shock wave accelerating electrons. Using LOFAR’s spectro-polarimetric and imaging observations, we track the locations of the type II radio sources across multiple frequencies. We find two distinct sources: one corresponding to the higher-frequency component and the other corresponding to the lower-frequency component of the split harmonic band. We also find no significant change in the degree of circular polarisation between the two bands. Our results suggest that the components of the split emission lane originate in two close but distinct regions upstream of the shock.
Author(s): Mohamed Nedal, Peter Gallagher, David Long, Catherine Cuddy
Dublin Institute for Advanced Studies (DIAS); Dublin Institute for Advanced Studies (DIAS); Dublin City University; Dublin Institute for Advanced Studies (DIAS)
Abstract: Understanding the intricate mechanisms of high-energy particle production and propagation from the Sun is imperative for advancing our knowledge of solar physics and enhancing space weather prediction capabilities. This project aims to elucidate the processes governing electron acceleration within the solar atmosphere and their subsequent journey into the solar system.
Exploiting data from cutting-edge radio telescopes such as the Low-Frequency Array (LOFAR) and Nançay RadioHeliograph (NRH), in conjunction with observations from X-ray and extreme ultraviolet (EUV) instruments, we intend to pinpoint the regions in the solar corona where energy release events occur and electron acceleration takes place. Utilizing sophisticated computational models, we will simulate the trajectories of these accelerated electrons along magnetic field lines as they escape into the heliosphere.
Direct measurements of these energetic electrons will be obtained through NASA’s Parker Solar Probe and ESA’s Solar Orbiter spacecraft, positioned closer to the Sun than previous missions. The project is structured into two distinct phases: (1) studying electron acceleration during periods of low solar activity, with a particular emphasis on small-scale magnetic reconnection events, and (2) studying electron acceleration during heightened solar activity, focusing on solar flares and Coronal Mass Ejections (CMEs) and their associated shock waves.
This work tackles the first part of the project, in which we investigate the sources of the solar type III radio bursts that occurred on September 18, 2021. The Sun had no sunspots on the solar disk that day. Type III radio bursts are caused by electron beams accelerated along open magnetic field lines from the Sun, and they are usually associated with magnetic reconnection events that occur in the vicinity of sunspots on the Sun. Preliminary results of the investigation are reported.
By scrutinizing major solar eruptions and the ensuing shock waves during active phases and investigating subtle magnetic reconnection events during quiescent periods, we anticipate uncovering novel insights into the fundamental physics of particle acceleration and transport from the Sun. The outcomes of this research endeavour hold significant implications for advancing space weather forecasting capabilities, thereby aiding in the mitigation of potential adverse effects on technological infrastructures and human activities on Earth.
Author(s): Aleksandr Rubtsov, Sergey Anfinogentov
Institute of Solar-Terrestrial Physics SB RAS, Irkutsk, Russia; Institute of Solar-Terrestrial Physics SB RAS, Irkutsk, Russia
Abstract: In this study, we analyzed images of the near-Earth space recorded by IMAGE/EUV at 304 Å wavelength and found possible signatures of the interplanetary coronal mass ejection (CME). IMAGE/EUV was designed for plasmasphere studies and shows the spatial distribution of helium ions. IMAGE satellite was in operation in 2000–2005. On January 9, 2005, a few bright fronts traveling at the background of the Earth in anti-sunward direction were observed. The brightness of these fronts is comparable with the brightness of the plasmasphere during the observation, meaning the same helium ion density (50–100 cm−3). We suggest these fronts to be a projection of the shock front of the CME observed by SOHO/LASCO on January 5. The fronts had different speed projected on the plane of the image and, considering IMAGE rotation around the Earth, may show plasma structures at different CME legs, further and closer to the Earth. The interplanetary CME was detected by ACE and Wind satellites near L1. We calculated the possible time window for the January 5 CME arrival from SOHO/LASCO data, and it consists with both ACE and Wind, and IMAGE data. Moreover, this is the only CME that could cross the IMAGE/EUV field of view on January 9. Observation of the interplanetary CME at EUV range may show new details of the CME’s spatial structure. It is not yet clear, why this observation is so unique, when a lot of CMEs occurred in 2000–2005, and further analysis is needed.
Author(s): Emiliya Yordanova, M. Temmer, M. Dumbovic, C. Scolini, E. Paouris, A.L.E. Werner, A. P. Dimmock, L. Sorriso-Valvo
Swedish Institute of Space Physics, Uppsala, Sweden; Institute of Physics, University of Graz, Austria; Hvar Observatory, Faculty of Geodesy, University of Zagreb, Croatia; Royal Observatory of Belgium, Brussels, Belgium; Department of Physics and Astronomy, George Mason University, Fairfax, VA, USA; Swedish Defence Research Agency, Stockholm, Sweden; Swedish Institute of Space Physics, Uppsala, Sweden; Institute for Plasma Science and Technology, CNR, Bari, Italy
Abstract: Coronal mass ejections (CMEs) play a crucial role in space weather impact on Earth. Therefore, accurate forecasting of CME arrival is essential to prevent potential damage to human technology and infrastructure. Our analysis focused on a consistent set of 12 Earth-directed fast halo CMEs from solar cycle 24, which caused intense geomagnetic storms. The propagation of the CMEs was investigated with EUHFORIA, ENLIL, DBM, and EAM models using the same initial CME kinematics. We assessed the models’ performance as follows: a) by using default model parameter values with simple CME configurations, as would be used in operations; b) by using simple CME configurations with refined values for the drag parameters in the modeling setup, c) by testing realistic and more complex multi-CME run scenarios. The forecast accuracy was based on the following metrics: mean error (ME), mean absolute error (MAE), and root mean square error (RMSE). The modeling with default input resulted in overall underestimated CME arrival time (MAE: 9.8 ± 1.8–14.6 ± 2.3 hr) and overestimated CME impact speed (MAE: 178 ± 22–376 ± 54 km/s) compared to the observations at L1. Further, inserting more than one CME, on average, did not derive an improved CME forecast. To address this discrepancy, we varied the dcld (CME-to-solar-wind density ratio) parameter in the ENLIL and EUHFORIA models, and the drag parameter γ in the DBM model. This refinement led to a reduction in the mean absolute error (MAE) for the forecasted arrival time (8.6 ± 2.2–13.5 ± 2.2 hr) and impact speed (51 ± 6–243 ± 45 km/s). Based on the findings of this study, we suggest adjustments to the operational settings for improving the forecast of fast halo CMEs.
Author(s): Tatiana Podladchikova, Shantanu Jain, Astrid M. Veronig, Stefan Purkhart, Galina Chikunova, Karin Dissauer, Mateja Dumbovic
Skolkovo Institute of Science and Technology; Skolkovo Institute of Science and Technology; University of Graz, Institute of Physics, University of Graz, Kanzelhöhe Observatory for Solar and Environmental Research; University of Graz, Institute of Physics; Hvar Observatory, Faculty of Geodesy, University of Zagreb; Skolkovo Institute of Science and Technology; NorthWest Research Associates, USA; Hvar Observatory, Faculty of Geodesy
Abstract: We present a rare case of a three-part solar coronal mass ejection (CME) observed in the low corona on March 28, 2022, in active region AR 12975. Namely, we observe a bright core/prominence, dark cavity and a bright CME leading edge in SolO/EUI and STEREO-A/EUVI. We perform 3D reconstructions of the filament eruption at different time-steps from three vantage points: SolO, STEREO-A, and SDO spacecraft. The filament height increased from 28 to 616 Mm over 30 minutes, with a peak velocity of 648 ± 51 km/s and a peak acceleration of 1624 ± 332 m/s². At 11:45 UT, the filament deflected by approximately 12 degrees, reaching a height of 841 Mm. The bright CME leading edge, which appears to be a quasi-spherical CME shock, grows from 383 Mm to 837 Mm between 11:25 and 11:35 UT. The distance between the filament apex and the CME leading edge more than doubled from around 93 to 212 Mm over 10 minutes. Using the DIRECD method, we in addition studied the expansion of observed coronal dimming as an indicator of the early CME propagation. This method uses a cone model to approximate an expanding CME at the end of the dimming’s impulsive phase, estimating parameters such as direction (along the filament motion, inclined 6 degrees from the radial expansion), half-width (21 degrees), and cone height (1.12 Rs), where the CME remains connected to the dimming and leaves footprints in the low corona. The resulting CME parameters are derived by matching CME projections on the solar sphere with the dimming geometry. Notably, the reconstructed cone closely aligns with the observed filament shape, which is the inner part of the CME. By extrapolating filament and CME outer edge heights to LASCO COR2 times, we determined that the cone closely matched the shape of the CME, with the fainter CME parts closely corresponding to far-side cone projections. These findings offer valuable insights into early CME propagation, crucial for improving space weather forecasting and mitigating its impacts.
Author(s): Mateja Dumbovic, Karmen Martinic, Galina Chikunova, Akshay Kumar Remeshan, Davor Sudar, Bojan Vrsnak, Jasa Calogovic, Manuela Temmer
Hvar Obs, Faculty of Geodesy, University of Zagreb; Hvar Obs, Faculty of Geodesy, University of Zagreb; Hvar Obs, Faculty of Geodesy, University of Zagreb; Hvar Obs, Faculty of Geodesy, University of Zagreb; Hvar Obs, Faculty of Geodesy, University of Zagreb; Hvar Obs, Faculty of Geodesy, University of Zagreb; Hvar Obs, Faculty of Geodesy, University of Zagreb; University of Graz
Abstract: The DBM (Vrsnak et al., 2013) for the propagation of ICMEs in the heliosphere is a widely used, simple analytical model that can predict the arrival time and speed of ICMEs at any heliospheric distance. The current version of the DBM and its ensemble version DBEMv3 are in operation as part of the ESA Expert Service Centre for Heliospheric Weather (https://swe.ssa.esa.int/graz-dbem-federated). The current versions consider a 2D CME geometry in the solar equatorial plane and runs the CME leading edge as a non-self-similarly expanding 2D cone. In addition, the model can take CME inputs from CME 3D reconstruction models such as the Graduated Cylindrical Shell (GCS) model to calculate the extent of the CME in the solar equatorial plane. In this way, the model can estimate whether an ICME will reach the observer based on the Stonyhurst longitude. However, it does not take into account the heliographic latitude or the extent of the CME in the solar meridional plane. Therefore, the model might not work as well for CMEs that are far from the solar equatorial plane. Moreover, the current tool cannot model CME-CME interactions. We implement the 3D CME geometry into the DBM by applying the geometry of the non-self-similarly expanding 2D cone in both the solar equatorial plane and the meridional plane. With this addition, the model can calculate the extent of the CME in both the solar equatorial plane and the meridional plane and consequently estimate whether an ICME will reach the observer, taking longitude and latitude into account. To asses the possible improvements in the predictive capability of the model, we first test it on a control sample of synthetically generated CMEs and then on a real sample of observed CME-ICME pairs. In addition, we provide a DBM modelling scheme, with 3D CME geometry implemented, for CME-CME interactions and present it using an example case study.
Author(s): Abril Sahade, Angelos Vourlidas, Cecilia Mac Cormack, Laura Balmaceda
NASA Goddard Space Flight Center; The Johns Hopkins University Applied Physics Laboratory; NASA Goddard Space Flight Center; NASA Goddard Space Flight Center
Abstract: It is known that not all coronal mass ejections (CMEs) evolve radially, deflections in the trajectory are attributed mainly to the interaction with magnetic structures surrounding the source region, coupling between successive events, and asymmetric detachment of the magnetic flux rope (MFR). However, in which amount and how each of these processes influences the deviation of the MFR acts is still under study. The research conducted in this work focuses on understanding the interaction between the MFR and the source region environment. We studied the trajectory of CMEs related with prominence eruptions, observed simultaneously by SDO, STEREO-A and Solar Orbiter. We reconstructed the three-dimensional path of the events using tie pointing technique and the Graduated Cylindrical Shell (GCS) model.
We investigate the role of the magnetic gradient as a predictor of the final path of a CME and also introduce a new concept: the topological path. The topological path is derived considering the connectivity of the source region with the background magnetic field. It not only better predicts the final position of the CME but also follows the low coronal deflection of the prominence, compared to the minimal magnetic gradient path.
We consider this new proxy can be useful for improving the space weather forecasting, as it can be computed by simply determining the coordinates of the source region and its background magnetic field.
Author(s): Diego Lloveras, Hebe Cremades, Francisco Iglesias, Florencia Cisterna, Alberto Vásquez, Federico Nuevo, Ward Manchester IV, Nishtha Sachdeva
Grupo de Estudios en Heliofísica de Mendoza (GEHMe), Universidad de Mendoza, Argentina; Grupo de Estudios en Heliofísica de Mendoza (GEHMe), Universidad de Mendoza, Argentina; Grupo de Estudios en Heliofísica de Mendoza (GEHMe), Universidad de Mendoza, Argentina; Grupo de Estudios en Heliofísica de Mendoza (GEHMe), Universidad de Mendoza, Argentina; Instituto de Astronomía y Física del Espacio, CONICET–UBA, Argentina; Instituto de Astronomía y Física del Espacio, CONICET–UBA, Argentina; Climate and Space Sciences and Engineering, University of Michigan, USA; Climate and Space Sciences and Engineering, University of Michigan, USA
Abstract: Coronal mass ejections (CMEs), huge structures of plasma and magnetic field expelled from the solar corona into the solar wind, play a determining role in the evolution of space weather. A detailed understanding of the physical mechanisms that govern CME dynamics is crucial for space weather forecasting and requires the combination of observations with theoretical modeling and numerical simulation. This work combines observations with advanced modeling techniques. We use the AWSoM (Alfvén Wave Solar Model) to simulate the pre-event solar corona and wind. To simulate the CME, we use the EEGGL (Eruptive Event Generator Gibson-Low) module, which injects an initial flux-rope type magnetic configuration that is allowed to evolve into the interplanetary medium. Our observational validation approach has two parts. On the one hand, we use tomographic reconstructions to validate the background corona (AWSoM pre-event simulation). On the other hand, we use a Deep Neural Network (DNN) trained to identify the outer shell of CMEs in images. This allows us to calculate key parameters of the CME (e.g. angular width, central position angle, apex, direction of propagation) from simulated images and compare them to those obtained from real images captured by the STEREO/COR2 A-B telescopes. In this presentation, we use images provided by STEREO/COR2A-B and Lasco-C2/SoHO, to validate the model’s capability to successfully simulate a selected CME event.
Author(s): Momchil Dechev, Rositsa Miteva, Kamen Kozarev, Zoran Simic, Kostadinka Koleva, Nenad Sakan
Institute of Astronomy and NAO, Bulgarian Academy of Sciences, Bulgaria; Institute of Astronomy and NAO, Bulgarian Academy of Sciences, Bulgaria; Institute of Astronomy and NAO, Bulgarian Academy of Sciences, Bulgaria; Astronomical Observatory Belgrade, Serbia; Space Research and Technology Institute, Bulgarian Academy of Sciences, Bulgaria; Astronomical Observatory Belgrade, Serbia
Abstract: Active processes on the Sun, are different manifestations of a single physical process whose source and motor are the free energy stored in the coronal magnetic fields. These various manifestations of solar activity have a significant impact in the heliosphere as well as many processes on Earth and human activity. In the “Sun and Solar System” group at the Institute of Astronomy with the National Astronomical Observatory (IANAO) we study of the active processes on the Sun. We are cataloging solar proton events, as well as electromagnetic signatures from solar flares in the metric radio band associated with solar energetic electrons. In the Belgrade Astronomical Observatory there are traditions in the theoretical modeling of a number of spectral lines.
The main goals of this project are to exchange the experience gained in modeling spectral lines at the Belgrade Observatory and to apply them in studying observable active processes of the Sun. Recently compiled catalogs of solar energetic particles (protons and electrons), solar flares, radio emission signatures and geomagnetic storms are also presented.
Author(s): Giuliana Russano, Yara De Leo, Federica Frassati, Giovanna Jerse
INAF – Astronomical Observatoty of Capodimonte, Napoli; Max-Planck-Institut für Sonnensystemforschung, Germany; Università di Catania, Italy; INAF – Astrophysical Observatory of Torino; INAF – Astronomical Observatory of Trieste
Abstract: The Metis coronagraph on board Solar Orbiter (SolO) performs for the first time simultaneous images of the solar corona in broad-band visible light (580 − 640 nm) and in the ultraviolet (UV) narrow spectral range, centered on the Lyman α line of hydrogen at 121.6 nm.
In particular, the Metis instrument is designed for dedicated observation programs during the Solar Orbiter’s perihelion passages, providing high temporal (>1s) and spatial resolution (< 4000 km (20”)) images, with a field of view extending from 1.7 to 3 solar radii at a distance of 0.28 AU from the Sun.
During the October 2022 perihelion, Metis captured an exceptionally large coronal mass ejection (CME) revealing detailed structural features of these eruptions with unprecedented resolution. In this study, we present a comprehensive analysis of the eruption event, providing significant findings regarding its kinematics state, temporal evolution and the outflow velocity within the expanding solar corona. Additionally, we integrate observations from other space-based coronagraphs and disk imagers to track the event from its initiation in the low corona to its expansion up to higher layers of the solar atmosphere.
Author(s): Preity Sukla Sahani, Vincenzo Andretta, Giuliana Russano
INAF – Astronomical Observatory of Capodimonte, Naples / University of Naples Federico II; INAF – Astronomical Observatory of Capodimonte, Naples; INAF – Astronomical Observatory of Capodimonte, Naples
Abstract: The Metis Coronagraph onboard the Solar Orbiter (SolO) mission is a powerful
instrument to study the onset and evolution of various eruptive solar events by
measuring their plasma properties (temperature, energy budget, density
distributions, etc.), as well as their kinematic states (speed, acceleration, geometry,
etc). It studies the solar corona with very high spatial (< 4000 km) and temporal (≥
1s) resolution during its perihelion passages, where at the closest approach, the field
of view can extend from 1.7 to 3 solar radii.
To achieve these goals, Metis produces simultaneous images in both the Visible (VL) broad-band light (580-640 nm) and in the Ultraviolet (UV) narrow spectral range centred on the Lyman α line of Hydrogen at 121.6 nm. This multi wavelength approach allows a comprehensive analysis of eruptive events.
In particular, the Metis team is building a database of solar eruptive events detected using the Metis Coronagraph in both the VL and UV channels. A significant number of events in the catalogue may have been geoeffective and may thus be associated with space weather events. We plan to present an overview of this subset of the Metis catalogue with a specific emphasis on selected geoeffective events.
Author(s): Christopher Light
NASA – CCMC
Abstract: In studying Solar Energetic Particles (SEPs), we often focus on the issue of acceleration, but the process of particle transport to the area of interest is also important in defining the time profile and intensity of an SEP event. We will show evidence of Forbush-like shielding of SEPs, highlighting the importance of considering heliospheric conditions and particle transport when forecasting SEPs.
Author(s): Franco Manini, Hebe Cremades, Teresa Nieves-Chinchilla, Diego Lloveras, Francisco Iglesias, Fernando M. López, Leonardo Di Lorenzo
Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofisica de Mendoza, Mendoza, Argentina / Universidad Nacional de San Juan, San Juan, Argentina; Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofisica de Mendoza, Mendoza, Argentina; Heliospheric Physics Laboratory, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20770, USA; Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofisica de Mendoza, Mendoza, Argentina; Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofisica de Mendoza, Mendoza, Argentina / Max Planck Institute for Solar System Research, Göttingen, Germany; Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofisica de Mendoza, Mendoza, Argentina; INFAP Giorgio Zgrablich, FCFMyN-UNSL-CONICET, 5700, San Luis, Argentina
Abstract: Magnetic flux ropes, twisted magnetic structures embedded within coronal mass ejections (CMEs), remain a significant unknown regarding their three-dimensional shape and internal magnetic field configuration. Due to their potential to disrupt Earth’s magnetosphere and impact spacecraft, understanding the evolution of these flux ropes within the inner heliosphere is crucial for space weather forecasting and mitigation strategies. As part of this work, we selected three Earth-directed CMEs seen in the field of view of the Heliospheric Imager 1 (HI-1) telescope aboard the Solar Terrestrial Relations Observatory – Ahead (STEREO-A) spacecraft, whose flux rope’s main axis is horizontally oriented. We test different distortion functions using the General Distorted-Toroidal flux rope model, and measure the deformation of the flux rope cross section as the CMEs propagate in the fields of view of the COR2 coronagraph and HI-1. As ultimate goal, we plan to perform the comparison between the modeled magnetic field profile, resulting from extrapolating the measured shape of the flux rope to 1AU, and the in-situ magnetic field observations from the Wind and Advance Composition Explorer (ACE) spacecraft, which is key to understand flux rope distortions otherwise masked in the in-situ data.
Author(s): Franco Manini, Hebe Cremades, Fernando M. López, Teresa Nieves-Chinchilla
Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofisica de Mendoza, Mendoza, Argentina / Universidad Nacional de San Juan, San Juan, Argentina; Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofisica de Mendoza, Mendoza, Argentina; Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofisica de Mendoza, Mendoza, Argentina; Heliospheric Physics Laboratory, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20770, USA
Abstract: We compiled a database of low frequency (kilometric) radio emission events through the analysis of all dynamic spectra of the TNR instrument, part of the WAVES experiment onboard NASA’s Wind mission. The list encompasses the years 1994-2021, i.e. covering more than two full solar cycles. We found a total of 320 radio emission events, out of which 136 had not been cataloged before. As part of this database also, we interrelate the detection of kilometric Type II (kmTII) radio emissions with interplanetary structures such as shock waves and ICMEs. Moreover, for 121 shock waves that could be associated with these radiofrequency events, we analyze their physical characteristics and compare them to those of the shock waves not associated with radio emission events. The goal is to find which conditions favor the production of kmTII radio emission, and what are the in-situ differences between them. The results show that shock waves associated with kmTII radio emissions are faster, produce greater changes in density, in magnetic field, and specially changes in the plasma beta depending on the type of shock wave.
Author(s): Carlos Larrodera, Manuela Temmer
University of Alcalá; University of Graz
Abstract: Our research focuses on the sheath regions, characterized as heated and turbulent material preceding the magnetic obstacle of the ICME.
Using the catalog of interplanetary coronal mass ejections (ICMEs) were we conducted a comprehensive statistical analysis of the evolution of magnetic obstacles with and without a sheath presented by Larrodera & Temmer (2024), our study aims to elucidate the evolution of ICME sheaths and their relationship with the formation mechanisms proposed by Siscoe & Odstrcil (2008) and Salman et al. (2021). Preliminary results indicate significant differences in the fluctuations of the mean and standard deviation of the magnetic field between two distinct solar cycles. These findings suggest that the characteristics of ICME sheath regions may vary depending on the solar cycle phase. This research represents an initial step towards a more comprehensive understanding of the dynamics and variability of ICME sheaths, with implications for space weather forecasting and modeling. We aim to contribute to the broader knowledge of solar-terrestrial interactions and their impact on space weather phenomena.
Author(s): Angelos Valentino, Jasmina Magdalenic, Brenda Dorsch
Centre for Mathematical Plasma Astrophysics, KU Leuven, Leuven, Belgium; Centre for Mathematical Plasma Astrophysics, KU Leuven, Leuven, BelgiumSolar-Terrestrial Center of Excellence-SIDC, Royal Observatory of Belgium, Av. Circulaire 3, B1180 Brussels, BelgiumSolar-Terrestrial Center of Excellence-SIDC, Royal Observatory of Belgium, Av. Circulaire 3, B1180 Brussels, Belgium Solar-Terrestrial Center of Excellence-SIDC, Royal Observatory of Belgium, Av. Circulaire 3, B1180 Brussels, BelgiumSolar-Terrestrial Center of Excellence-SIDC, Royal Observatory of Belgium, Av. Circulaire 3, B1180 Brussels, Belgium; Centre for Mathematical Plasma Astrophysics, KU Leuven, Leuven, Belgium
Abstract: We present the study of halo CMEs with propagation direction that noticeably deviated from the Sun-Earth line through observations and modeling. As a result of such a propagation direction all studied CMEs impacted Earth as flank-encounters. We modeled selected events using the default-setup of EUHFORIA and a) the Cone and b) FRi3D CME models. The first method that we used in order to obtain the input parameters is the DONKI database while the second is by fitting the CMEs with the GCS technique (Thernisien et. al 2006, 2009). The aim of our study is to better understand the importance of the direction of propagation in the input parameters to different CME models and improve the modeled arrival time at Earth. We selected events that were propagating strongly non-radialy, in order to understand how important are the effects of the deflections in the low corona, in the direction of propagation.
Our results show that, when the DONKI data are used, the modeled arrival time is the furthest (≥10h) from the observed one. When the input parameters are taken from the GCS fitting though, up to the height of 12 Solar radii, the modeled arrival time shifts very close to the observed one. This is because at this height the CMEs have experienced all the low corona deflections and have taken their final direction of propagation.
We also used two other methods, to compare our modeling results for the estimation of the arrival time at Earth. The first one is the type II radio bursts with which we take a difference for the shock arrival at Earth of up to ±30 hours. The second one is the 2D-speed obtained from the coronagraph white light images, with which we take a difference for the shock arrival at Earth of up to ±40 hours.
Author(s): Kostadinka Koleva, Momchil Dechev, Nat Gopalswamy, Seiji Yashiro
Space Research and Technology Institute, Bulgarian Academy of Sciences, Sofia, Bulgaria; Institute of Astronomy and NAO, Bulgarian Academy of Sciences, Bulgaria; NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA; The Catholic University of America, Washington, DC 20064, USA
Abstract: We investigate the latitudinal offsets of CMEs with respect to their source regions during SC 24 and SC 25. The CME’s radial offset from the associated prominence eruptions (PEs) are analyzed by comparing their latitudes in the plane of the sky. The relation between CME linear speed and PE-CME latitudinal offset were studied. The non-radial offsets for the rising and decay phases of SC 24 are compared. We also examined the relationship between the critical height and the initial CME kinematics. The systematic equatorward offset of CME from the solar source region for the rising phase of Solar Cycle was found.
Author(s): Anwesha Maharana, Luis Linan, Stefaan Poedts, Jasmina Magdalenic
KU Leuven, Belgium; KU Leuven; KU Leuven, Belgium; KU Leuven
Abstract: Coronal mass ejections (CMEs) are giant expulsions of magnetized plasma from the Sun that manifest flux rope structures. These flux ropes can be simulated with models with different types of geometry and internal magnetic field structures, and thus possess different capabilities for operational space weather forecasting. Flux rope CME models such as the spheromak model (Chandrasekhar & Kendall, 1957) with spherical geometry and the ‘Flux Rope in 3D’ (FRi3D) model (Isavnin 2016) with a global twisted magnetic flux tube geometry are already widely used in studying CME evolution and propagation in the heliosphere within the EUropean Heliosphere FORecasting Information Asset (EUHFORIA). Although the more realistic flux rope geometry of FRi3D is a significant upgrade over the spheromak model, its complex geometrical transformations are a drawback for efficient, fast and stable simulations. In this study, we discuss an optimal setup where the geometry is more realistic than the spherical plasma blob while the simulations are still fast and robust enough for operational forecasting setup. This ‘Horseshoe’ CME model has been implemented in EUHFORIA and is a modification of the full torus model introduced by Linan et al. (2024). The geometrical implementation of the Horseshoe model is missing the torus’s back part, making it a more realistic flux rope structure with two legs. In this model, we adopt the analytical constant alpha force-free magnetic field configuration of the modified Miller and Turner solution (Vandas et al., 2015). The advantages of the Horseshoe model over FRi3D are the easy implementation of its analytical formula and the low(er) computational cost. Moreover, the modelled CME can be pushed entirely through the inner boundary, thus not interfering with the numerical injection of the successive CMEs.
For validation, we model the CME-CME interaction event of 8-10 September 2014, whose geomagnetic impact was erroneously predicted by the space weather community (Maharana et al., 2023). The interplanetary CME did not carry a southward magnetic field in its magnetic cloud, but rather in its sheath. This event is rather complex from the perspective of interpreting the low coronal signatures of the CMEs and determining the correct parameters for the initialization of the EUHFORIA simulations. With our flux rope CME models, we predict the arrival times of the CMEs and try to understand the formation of a geo-effective sheath resulting from the interaction of the subsequent CMEs. We also discuss the characteristics of the CME models suitable for operational space weather forecasting and for studying the physics of the CMEs using EUHFORIA.
Author(s): Galina Chikunova, Mateja Dumbović, Bernd Heber, Akshay Kumar Remeshan
University of Zagreb, Faculty of Geodesy, Hvar Observatory; University of Zagreb, Faculty of Geodesy, Hvar Observatory; Christian-Albrechts University in Kiel; University of Zagreb, Faculty of Geodesy, Hvar Observatory
Abstract: We aim to compile an extensive catalog of Forbush decreases (FDs) caused by interplanetary coronal mass ejections (ICMEs), using ground-based as well as instruments from various spacecraft across heliosphere. Forbush decreases are short term depressions of galactic cosmic ray flux and one of the common signatures of interplanetary coronal mass ejections. We use magnetic field and plasma measurements to identify ICMEs and particle detectors with large counts to identify FDs. In the current version, the catalog covers varying heliocentric distances and covers decades of available observations (1974-1981, 1995-2024) during the different stages of the solar cycles. To minimize observer bias, we offer two to three different interpretations of the ICME event boundaries for each event. For each interpretation we document the start and end times of the ICME/FD event, associated magnetic field strength B values (average, standard deviation, maximum, median), flow speed v of the magnetic cloud (lead, trail, average, center), the time of the maximum FD value and its amplitude. Such comprehensive, multi-instrument catalog is crucial for statistical studies of FDs and associated in situ properties of ICMEs, as well as their evolution in the heliosphere. We ultimately intend to implement this data for validation of the analytical model ForbMod (Dumbovic et al., 2018) across a large sample of events.
Funded by European Union (project SPEARHEAD, No 101135044). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Health and Digital Executive Agency (HaDEA). Neither the European Union nor the granting authority can be held responsible for them. Some parts of this research are funded by the European Space Agency (project ForbMod2, No 4000144380/24/NL/MH/yd).
Author(s): Christian Gutierrez, Sergio Dasso, Pascal Demoulin, Miho Janvier
Instituto Astronomía y Física del Espacio; Instituto Astronomía y Física del Espacio; LESIA, Observatoire de Paris,; European Space Agency, ESTEC
Abstract: Galactic Cosmic Rays (GCRs) are high-energy particles that originate outside the solar system and permeate the heliosphere. The impact of Interplanetary Coronal Mass Ejections (ICMEs) and Stream Interaction Regions (SIRs) on the transport of GCRs, especially on the flux observed at ground level, has been studied for several decades. ICMEs, which originate from active solar regions, create Interplanetary Shocks (IS) when their speed surpasses the magnetosonic speed in the solar wind reference frame. Within ICMEs containing IS, a sub-structure known as the sheath extends from the IS to the beginning of the magnetized plasma ejected. On the other hand, SIRs form due to the interaction between slow and fast solar wind streams. Both ICMEs sheaths and SIRs form distorted Parkerian solar wind.
This study examines the effects of ICME sheaths and SIRs on the flux of GCRs near Earth, focusing on their differences and similarities. The research includes an analysis of the sheaths of ICMEs and SIRs observed during the 23rd solar cycle and a significant part of the 24th cycle. Using interplanetary magnetic field and solar wind plasma data, a thorough statistical analysis is performed. Ground level variability of the flux of GCRs is analyzed using high latitude neutron monitors. The techniques for the data analysis include a time normalization and a superposed epoch analysis.
While the profiles of SIRs and ICME sheaths are different, the findings show a significant correlation between the GCR profiles produced by both interplanetary structures.
Author(s): Nicolas Wijsen, Nina Dresing, Immanuel Jebaraj, Luis Linan, Erika Palmerio, Christian Palmroos, Athanasios Kouloumvakos, Manon Jarry, Eleanna Asvestari, Laura Rodriguez-Garcia, Christina Cohen, Christina Lee, Wenwen Wei
KU Leuven; University of Turku; University of Turku; KU Leuven; Predictive Science Inc., San Diego, USA;; University of Turku; Applied Physics Laboratory at the Johns Hopkins University; IRAP, CNRS; University of Helsinki; Space Research Group, Alcala de Henares, Spain; Caltech, Pasadena, USA; Space Sciences Lab, UC Berkeley, USA; Space Sciences Lab, UC Berkeley, USA
Abstract: On 13 March 2023, a powerful solar eruption occurred on the Sun’s far side, relative to Earth, leading to a widespread solar energetic particle (SEP) event. This SEP event was detected by several spacecraft in the inner heliosphere, including Parker Solar Probe, Solar Orbiter, BepiColombo, STEREO A, and near-Earth spacecraft. Parker Solar Probe, positioned on the far side of the Sun, observed the coronal mass ejection (CME) with its embedded magnetic cloud in situ. Remarkably, all the other spacecraft also recorded evidence of an in-situ shock and a related energetic storm particle event, even those located far from the eruption site. We propose that these observations could be explained by a single, circumsolar shock wave. To test this hypothesis, we utilize the magnetohydrodynamic (MHD) model EUHFORIA to simulate the solar wind and CME propagation, and the MHD model COCONUT to simulate the flux-rope eruption in the solar corona, aiming to determine if a circumsolar shock can be produced.
Author(s): Silvia Perri, Francesco Pucci, Federica Chiappetta, Francesco Malara, Giuseppe Nisticò, Luca Sorriso-Valvo, Gaetano Zimbardo
Università della Calabria; CNR, Institute for Plasma Science and Technology (ISTP); Università della Calabria; Università della Calabria; Università della Calabria; KTH, Division of Space and Plasma Physics; CNR, Institute for Plasma Science and Technology (ISTP); Università della Calabria
Abstract: One of the main goals of space weather science is to understand how energetic particles accelerated at the Sun, the so-called solar energetic particles (SEPs), propagate through the inner heliosphere eventually reaching the near Earth environment. Indeed, those particles represent a natural hazard for the functioning of commercial and scientific satellites. On the other hand, shock waves driven by coronal mass ejections (CMEs) are the most relevant particle accelerators in the interplanetary space, giving rise to SEP gradual events that can have a strong geomagnetic impact.
In this study, we aim at investigating the transport properties of energetic protons up to energies of hundreds of MeV by means of an innovative test-particle model, where SEPs interact with a 3D anisotropic turbulence. Beyond this, we first analyze magnetic field turbulence close to CME-driven shocks by using in-situ measurements from different satellites, at different radial distances, in order to capture the main properties of the environment close to the acceleration source. Thus, parameters such as the power spectral density of magnetic field fluctuations, the level of intermittency, the degree of turbulence anisotropy will serve as input for the test particle numerical code, since all these parameters can be tuned in the simulations. The possibility in the model of adapting turbulence parameters to observations allows us to obtain a description of SEP transport throughout the inner heliosphere. We find a strong influence of turbulence properties on the spatial diffusion coefficients parallel and perpendicular to the mean magnetic field and on the distribution of the scattering times. This study is achieved in the context of the project “Data-based predictions of solar energetic particle arrival to the Earth: ensuring space data and technology integrity from hazardous
solar activity events” (PRIN-PNRR-2022).
Author(s): Julio Hernandez Camero, Lucie M. Green, Alex Piñel Neparidze
Mullard Space Science Laboratory, UCL; Mullard Space Science Laboratory, UCL; University College London
Abstract: The identification of the source regions (SRs) of Coronal Mass Ejections (CMEs) is a challenging task. Some catalogues exist which rely on manual identification, making the characterization of failure cases difficult, and are sensitive to changes in the team behind the associations. As an alternative to the manual approach, we have developed an automated algorithm that matches LASCO CDAW CMEs to their SRs using post-eruptive signatures. In particular, we make use of flares from the GOES flare list and dimmings from Solar Demon as potential eruption signatures to associate CMEs with Space weather HMI Active Region Patch (SHARP) regions.
When we run our algorithm on LASCO CDAW CMEs recorded between 2010-05 and 2019-01 with no quality issue flags, our algorithm matched 1132 out of 4190 total recorded CMEs. Since we expect half of these CMEs to originate from the backside of the Sun, around 2095 should have been matched. This discrepancy highlights the difficulty in confidently matching all CMEs.
While the two signatures used in our algorithm are known to be related to CME eruptions, the relationship is not one-to-one. Hence, to understand the reliability of different association levels (e.g., flare > M class with dimming vs. dimming with no flare), we apply the algorithm to a control list of synthetic CMEs. These synthetic CMEs have position angles and widths drawn from the distributions of true CMEs, but are such that their time does not overlap with any real CME. We expect that the most reliable association levels will appear less frequently in the control list compared to the list of true CMEs. We also perform manual checks on around 300 of the matched CMEs to understand when the wrong SR has been identified.
Using our catalogue of CME SRs, we present a statistical analysis of the evolution and properties of CME eruptive regions and their relation to CME properties. We also highlight how our catalogue can be used for ML studies, be it for the forecast of these events or to predict the properties of CMEs using information from their source regions. We believe the strength of our automated approach resides in the significantly reduced time needed to produce these associations and the ability to quickly and easily evaluate the algorithm’s performance. This enables running regular verifications to detect potential degradation in performance due to changes in data sources or algorithm modifications. While our implementation is not currently operating in real time, we hope it serves as a proof of concept leading to the development of an automated CME SR detection tool for the community.
Author(s): Aswin Amirtha Raj S, Dr. A. Shanmugaraju, Vijayalakshim P
Arul Anandar College; Arul Anandar College; Arul Anandar College
Abstract: Recent advancements in machine learning have led to significant progress in space weather predictions. However, identifying suitable proxies to train these models remains challenging. One of the most difficult tasks in space weather prediction is forecasting whether an active region will produce a Coronal Mass Ejection (CME), and predicting the velocity of the resulting CME is even more complex.
In this study, we utilize SHARP parameters as proxies to tackle the challenging task of CME velocity prediction. Although existing models perform reasonably well in predicting the velocities of fast CMEs, they often fail to accurately predict the velocities of slow CMEs. The reasons for this discrepancy in predicting slow CME velocities are not yet fully understood. We hypothesise that proxies based on sunspot properties may be inadequate for predicting slow CME velocities.
Here, we investigate the relationship between the SHARP parameters of active regions and the velocities of fast and slow CMEs. Our results provide valuable insights into CME velocity prediction and help explain why sunspot magnetic properties may not serve as effective velocity predictors for slow CMEs.
Keywords: SHARP parameters, CME velocity prediction.
Author(s): Souvik Roy, Dibyendu Nandy
Indian Institute of Science Education and Research Kolkata; Indian Institute of Science Education and Research Kolkata
Abstract: We present a comprehensive analysis of idealized interplanetary coronal mass ejections (ICMEs) driven geomagnetic storms using simulations with the 3D magnetohydrodynamic (MHD) STORM Interaction module (CESSI-STORMI). By examining variations in flux rope twist, orientation, and interaction times throughout the year, we investigate the annual variations of geomagnetic storms and their dependency on these parameters. Our findings demonstrate a significant correlation between the simulated (STORMI) index – a proxy for the strength of geomagnetic storms – and the z-component of the interplanetary magnetic field (Bz) as observed. Our simulations uncover pronounced seasonal variations across equinoxes and solstices, showcasing a biannual pattern in geomagnetic activity – which explains the Russell-McPherron effect. We also discover that this pattern exhibits a sinusoidal relationship with the IMF clock angle. Furthermore, we identify a symmetric influence of flux rope twist on geomagnetic storm geoeffectiveness, with mirrored STORMI profiles for flux ropes of opposite twist polarities at specific epochs of the Earth’s revolution around the Sun. This symmetry persists across different months and tilt-twist combinations, indicating a strong correlation between opposite polarity tilt-twist sets. These insights into the dynamics of ICME-driven geomagnetic storms imply that the interplay of CME flux rope helicity, topology, and orientation plays a significant role in space weather impacts. Our work has important implications for star-planet interactions and space weather forecasting.
Author(s): Jasper Edwards, Guifré Molera Calvés
University of Tasmania & Commonwealth Scientific and Industrial Research Organisation; University of Tasmania
Abstract: The effectiveness of using interplanetary scintillation measurements of spacecraft radio signals to probe the solar corona, solar wind structure and solar transient events such as Coronal Mass Ejections (CMEs) has been demonstrated since the late sixties. Over half a century later, these observations are still very important for tracking the long-term variations in the corona and the interplanetary environment, especially at different stages of the solar cycle. At present, scintillation observations are the only alternate method to in situ spacecraft measurements for tracking CME structures outside of the field of view of coronagraph instruments.
Using the University of Tasmania’s Very Long Baseline Interferometry (VLBI) radio telescopes, we observed the X-band (8.4 GHz) radio downlink signals from Mars Express, Tianwen-1 and BepiColombo spacecraft during the 2023 Mars superior solar conjunction. The aim of this experiment was to study the solar wind by measuring the phase and frequency scintillation, and the spectral broadening of the radio signals with multiple VLBI antennas observing simultaneously. Using this technique, the scintillation pattern can be tracked as it transits across the sky from one station line of sight to another. Cross-correlation of the phase time series provides a direct measurement of the velocity of the plasma. In addition, depending on the relative direction of the antenna separation and the propagation direction of the solar wind, the axial ratio of the solar wind can also be determined.
On two separate epochs during this campaign, we observed the onset and transit of a CME across the radio propagation path to Earth. One of these observations occurred while both Mars Express and Tianwen-1 spacecraft were transmitting simultaneously. At the time of observations, the angular separation between Mars and the Sun was less than 4.5 degrees (i.e. the radio propagation path traveled within 17 solar radii of the Sun).
In this presentation, we will discuss the radio scintillation results from the CME transits and how they relate to the structure and turbulence of the CMEs. We compare the radio science results with ancillary data from coronagraph images to better understand the structure and characteristics of the CME impact on the radio signal.
Author(s): Roberto Susino, Alessandro Bemporad, Silvano Fineschi, Daniele Telloni, Rosario Messineo, Filomena Solitro, Federico Pinna, Leonardo Tolomei, Michele Piana, Sabrina Guastavino, Gianalfredo Nicolini, Francesco Amadori, Salvatore Mancuso
INAF – Astrophysical Observatory of Turin; INAF – Astrophysical Observatory of Turin; INAF – Astrophysical Observatory of Turin; INAF – Astrophysical Observatory of Turin; Altec S.p.A.; Altec S.p.A.; Altec S.p.A.; Altec S.p.A.; University of Genua; University of Genua; INAF – Astrophysical Observatory of Turin; INAF – Astrophysical Observatory of Turin; INAF – Astrophysical Observatory of Turin
Abstract: Coronal mass ejections (CMEs) are one of the principal drivers of Space Weather and their impact on Earth can potentially have severe consequences on several human activities. Once they are ejected from the solar corona, these impulsive magnetised clouds of plasma can reach the Earth in a few days, thus forecasting their arrival time as quickly as possible is of crucial importance.
CMEs are usually characterised through inspection of coronagraphic images (e.g., from SOHO/LASCO or STEREO/SECCHI observations) from which their geometrical properties are manually derived. Parameters such as initial velocity, angular width, propagation direction, and mass are then used as input to more or less sophisticated models that predict their arrival time and speed at specific targets in the solar system, in particular at Earth.
We present a new method to automatically detect halo or partial-halo CMEs in coronagraphic images obtained by SOHO/LASCO, to extract their geometrical parameters from the automated identification and fitting of their cross-section in the images, and to forecast their arrival time at 1 AU using a modified 2D version of the widely adopted Drag-Based Model (DBM). This approach – developed by INAF – Astrophysical Observatory of Turin, in collaboration with Altec S.p.A. and University of Genua, Italy – which combines fully automated operations with a relatively simple (and quick) propagation model, has been integrated into the CME Propagation Prediction Tool, recently proposed as a demonstration tool for the ESA Space Weather network (SWESNET).
Author(s): Ruggero Biondo, Alessandro Bemporad, Paolo Pagano, Fabio Reale, Federica Frassati, Salvatore Mancuso, Mesoraca A., Giuseppe Nisticò, Silvia Perri, Giuseppe Prete, Roberto Susino, Gaetano Zimbardo
INAF, Turin Astrophysical Observatory, Torino, Italy; INAF, Turin Astrophysical Observatory, Torino, Italy; University of Palermo, Palermo, Italy; INAF, Palermo Astronomical Observatory, Palermo, Italy; University of Palermo, Palermo, Italy; INAF, Palermo Astronomical Observatory, Palermo, Italy; INAF, Turin Astrophysical Observatory, Torino, Italy; INAF, Turin Astrophysical Observatory, Torino, Italy; University of Calabria, Rende, Italy; University of Calabria, Rende, Italy; University of Calabria, Rende, Italy; University of Calabria, Rende, Italy; INAF, Turin Astrophysical Observatory, Torino, Italy; University of Calabria, Rende, Italy
Abstract: On September 5, 2022, a Coronal Mass Ejection (CME) was multiply observed by coronagraphs on board the STEREO and SOHO spacecraft, and by the WISPR coronagraph on board the Parker Solar Probe (PSP). A few hours later, the plasma and magnetic field of the perturbation were measured in-situ by PSP at 0.07 AU and by Solar Orbiter at 0.7 AU. This event offers therefore a unique set of constraints for physical modeling.
Here, we present a numerical MHD simulation of the interplanetary CME propagation in the heliosphere. The Parker Spiral is accurately reconstructed from 5 solar radii to 1 AU using RIMAP, a data-driven hybrid analytical-numerical technique. The magnetic field and solar wind background conditions are reconstructed from PSP in-situ measurements before and after the CME encounter. From the conditions ballistically remapped at 5 solar radii, the whole Parker spiral is then reproduced by solving numerically the MHD equations with the PLUTO code. The CME enters the RIMAP-reconstructed spiral at 5 solar radii as a magnetic flux-rope adapted from the Titov-Démoulin model, with parameters constrained from coronagraphic observations. The MHD simulation describes the propagation of the CME out to 1 AU. An artificial tracer allows us to track the CME plasma.
The highly structured and realistic reconstruction of RIMAP allows us to draw conclusions on the interaction between the CME and the Parker Spiral with a good degree of accuracy. We compare the properties of the CME-driven shock to the in-situ measurements of PSP and Solar Orbiter, and, in the light of the few free parameters, discuss the validity and limitations of the model and also how this event would have been measured by a spacecraft at 1 AU.
Author(s): Akshay Kumar Remeshan, Mateja Dumbović, Manuela Temmer
University of Zagreb, Faculty of Geodesy, Hvar Observatory, Kaciceva 26 10000 Zagreb, Croatia; University of Zagreb, Faculty of Geodesy, Hvar Observatory, Kaciceva 26 10000 Zagreb, Croatia; Institute of Physics, University of Graz, Universitätsplatz 5, 8010 Graz, Austria
Abstract: We analyze 42 Interplanetary Coronal Mass Ejections (ICMEs) that showed interference with Stream Interaction Regions (SIRs) and/or their related High-Speed Streams (HSS) at 1AU in the time period between 2010 and 2019.The selected events contain 19 ICMEs with trailing HSSs and 23 with leading HSSs. The events are analysed using in situ magnetic field and plasma data. For each event we aim to analyse to which extent the interaction distorts typical ICME properties. For that purpose, we analyse the ICME flux rope type, duration of the sheath/Magnetic Obstacle (MO), MO velocity profile, MO distortion, duration of the HSS, location of the Stream Interface (SI), and the HSS maximum velocity. In addition, we search for possible reconnection exhaust signatures at the interface of the ICME and HSS, by applying the Minimum Variance Analysis and Walen test.
The interaction effects are characterized by comparing the relative position of SIs concerning the CME and HSS, flux rope distortion, velocity profile (Expanding or Not), and the existence of magnetic reconnection between the CME and HSS in a statistical study.
Author(s): Ute V. Amerstorfer, Hannah T. Rüdisser, Andreas J. Weiss, Christian Möstl
Austrian Space Weather Office, GeoSphere Austria, Graz, Austria; Austrian Space Weather Office, GeoSphere Austria, Graz, Austria; Institute of Physics, University of Graz, Graz, Austria; NASA Postdoctoral Program Fellow, NASA Goddard Space Flight Center, Greenbelt, USA; Austrian Space Weather Office, GeoSphere Austria, Graz, Austria
Abstract: One of the major unsolved problems in space weather forecasting at Earth is our inability to predict the north-south component of the interplanetary magnetic field at the L1 point with sufficient lead time to initiate mitigation procedures. Exploitation of in situ solar wind data at L1 together with machine learning or physical models is an often underappreciated approach, but holds promise to prolong these lead times.
In this study, we use a physics model, the semi-empirical 3D coronal rope ejection (3DCORE) method, to reconstruct the magnetic flux rope in an ICME when only the beginning of the flux rope is available for the reconstruction, similar to a real-time situation. Therefore, we apply 3DCORE to only the first hours of a few selected ICME events, in this way mimicking the real-time observation.
3DCORE assumes a tapered torus-like flux rope expanding self-similarly during its propagation and carrying along an embedded analytical magnetic field. An approximate Bayesian computation sequential Monte Carlo algorithm is used to perform the reconstruction and allows us to get error estimates of the model parameters.
If performing well, this real-time application of 3DCORE could further advance the efforts of space weather prediction.
SWR2-p35 Automated Magnetic Flux Rope Extraction and Example of a Multi-structured Coronal Flux Rope
Author(s): Andreas Wagner, Daniel J. Price, Slava Bourgeois, Jens Pomoell, Ranadeep Sarkar, Stefaan Poedts, Emilia Kilpua
University of Helsinki & KU Leuven; University of Helsinki; University of Coimbra & University of Sheffield; University of Helsinki; University of Helsinki; KU Leuven; University of Helsinki
Abstract: Studying magnetic flux ropes (MFRs) as the fundamental magnetic structure of coronal mass ejections is an important task for space weather forecasting. It helps in understanding the triggering mechanisms of solar eruptions as well as their structure and physical evolution. Furthermore, one may assess our modelling capabilities on the basis of comparing modelled MFRs with observational proxies. To enable such studies, we developed a MFR extraction scheme for identifying and tracking these magnetic structures in 3D simulation data. The method is furthermore wrapped into a graphical user-interface called GUITAR (Graphical User-Interface for Tracking and Analysing flux Ropes). It is based on combining a suitable MFR proxy, such as the twist parameter, with mathematical morphology algorithms. We showcase GUITAR on the example of a time-dependent data-driven magnetofrictional simulation of active region AR12473, where a MFR self-consistently develops and erupts from the simulation domain. Furthermore, we show that different sub-features of the MFR can be extracted with GUITAR, uncovering an erupting, multi-MFR system, that is also visible in multi-wavelength EUV images of SDO/AIA.
Author(s): Martin A. Reiss, Damian Barrous-Dume, Ronald Caplan, Cooper Downs, Matthew Lesko, Jon Linker, Peter MacNeice, Leila Mays, Maksym Petrenko, Andres Reyes, Viacheslav Titov, Tibor Török, Tina Tsui
Community Coordinated Modeling Center, NASA GSFC, Greenbelt, MD, USA; Community Coordinated Modeling Center, NASA GSFC, Greenbelt, MD, USA; Predictive Science Inc., San Diego, CA, USA; Predictive Science Inc., San Diego, CA, USA; Community Coordinated Modeling Center, NASA GSFC, Greenbelt, MD, USA; Predictive Science Inc., San Diego, CA, USA; Community Coordinated Modeling Center, NASA GSFC, Greenbelt, MD, USA; Community Coordinated Modeling Center, NASA GSFC, Greenbelt, MD, USA; Community Coordinated Modeling Center, NASA GSFC, Greenbelt, MD, USA; Predictive Science Inc., San Diego, CA, USA; Predictive Science Inc., San Diego, CA, USA; Predictive Science Inc., San Diego, CA, USA; Community Coordinated Modeling Center, NASA GSFC, Greenbelt, MD, USA
Abstract: NASA’s Community Coordinated Modeling Center (CCMC) introduces CORHEL-CME, the latest addition to our Runs-On-Request system in the solar and heliospheric modeling domain. Developed by Predictive Science Inc., CORHEL-CME is a highly automated and interactive MHD modeling framework designed to simulate multiple Coronal Mass Ejections (CMEs) within a realistic coronal and heliospheric environment. This innovative framework integrates three key features:
1. Interactive CME Design via GUI-Based Web Interface
CORHEL-CME’s user interface offers real-time diagnostics to assist users with model parameter settings, guides users through creating full physics-based CME simulations, and provides web-based visualization reports.
2. Modeling CMEs from Complex Active Regions
The inclusion of the RBSL flux rope model (Titov et al., 2018) allows users to simulate pre-eruptive flux ropes above elongated and curved polarity inversion lines, which enables realistic simulations of CMEs originating from complex active regions.
3. Efficient, Full Physics-Based CME Simulations
Through the web interface, users can set up simulation runs including a simplified (zero-beta) MHD model of multiple flux ropes, a quasi-steady-state coronal MHD background model, and a high-fidelity time-dependent CME simulation. All simulations are executed on AWS high-performance GPU servers maintained by the CCMC.
In our presentation, we will demonstrate the use of CORHEL-CME via CCMC’s Runs-on-Request system and showcase its application in modeling severe space weather events. This publicly accessible framework offers the community a powerful tool for advanced space weather modeling.
Author(s): Di Lorenzo, Leonardo, López, Fernando, Cremades Hebe, Balmaceda, Laura, Talpeanu, Dana-Camelia, D’Huys, Elke, Mierla, Marilena
INFAP “Giorgio Zgrablich”, FCFMyN – Universidad Nacional de San Luis, CONICET; Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofísica de Mendoza; Universidad de Mendoza, CONICET, Grupo de Estudios en Heliofísica de Mendoza; George Mason University, Heliophysics Science Division, NASA Goddard Space Flight Center; Solar–Terrestrial Centre of Excellence – SIDC, Royal Observatory of Belgium; Solar–Terrestrial Centre of Excellence – SIDC, Royal Observatory of Belgium; Solar–Terrestrial Centre of Excellence – SIDC, Royal Observatory of Belgium, Institute of Geodynamics of the Romanian Academy
Abstract: We investigate three coronal mass ejections (CMEs) that occurred during 2013 and exhibit characteristics of streamer blowouts (SBOs). SBO-CMEs are a subset of CMEs that lead to either the partial or complete removal of the pre-existing helmet streamer. They often exhibit a prolonged expansion phase, indicated by an increase in the width of the lower part of the streamer. The swelling can last for several hours or even days and is followed by the slow eruption of a CME at the streamer location.
Although their frequency varies between 1 and 12 SBOs per month, depending on the phase of the solar cycle, there are still unanswered questions about the origin, characteristics, and correlation of SBO-CMEs with solar atmospheric structures. Moreover, the nature of these events poses important challenges for their detection, for which multi-viewpoint observations at different coronal heights are crucial. We meticulously describe the evolution of the three studied events in the low corona using extreme ultraviolet (EUV) observations in multiple wavelengths from approximately 1 to 2.5 solar radii, while coronagraphic data in white light are used from 2.5 to 15 solar radii.
The corona in EUV is analyzed from data provided by the Sun Watcher using Active Pixel System detector and Image Processing (SWAP) aboard PROBA2 and the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). The white-light corona is studied using observations obtained by C2/C3 aboard the Solar and Heliospheric Observatory (SOHO) and COR1/COR2 aboard the Solar TErrestrial RElations Observatory (STEREO). We determine the morphology and kinematics of SBO-CMEs in terms of their three-dimensional (3D) location, velocity, and acceleration profiles. We focus on their early stages and evolution in the corona. In addition, we use a Potential Field Source Surface (PFSS) model to examine the magnetic field configuration in the region of the events. Our analysis aims to unravel the 3D morphology of SBO-CMEs during their early stages in the low corona, their evolution into the middle corona, and their impact on the configuration of the surrounding magnetic field. The results provide a more comprehensive understanding of SBO events and shed light on their intricate nature.
Author(s): Silvio Matteo Giiordano
INAF/OATo
Abstract: The Metis instrument is operating on board the Solar Orbiter since June 2020, the nominal phase mission started in December 2021, now the instrument is operating almost continuously.
The multi channels coronagraph provides simultaneous images in the Visible Light (VL) and Ultraviolet (UV) of the solar corona, covering a range of distances from about 2 up to over 10 solar radii with a high temporal (up to 1 second in VL and 1 minute in UV) and spatial scale (10 arcsec in VL and 20 arcsec in UV).
Metis provides kinematics and plasma properties of the transient events observed from
a complementary point of view with respect to mission such as SoHO, STEREO and Parker Solar Probe, then its coronagraphic data can allow for reconstructing the 3D structure of the events and contribute to the study of the propagation and the potential impact to Earth environment.
We have developed a tool to visualize the images time-series and to drive cataloguing the transient events by defining some characteristic parameters, such as latitude, angular size, velocity on the plane of the sky, and evidence of eruptive prominences, and to correlate the CMEs observed by Metis with the observations of the coronagraphs on board the SoHO and STEREO missions with the aim of reconstructing the 3D structure and kinematics of the events.
Finally, we are correlating the Metis CME with the events observed by other remote-sensing and in-situ instruments on Solar Orbiter (EPD, STIX, RPW and EUI) to identify solar activity and large heliocentric distance features associated with observed events.
A preliminary catalogue of CMEs has been made available online to the scientific community through the database accessible at the URL: https://metisarchive.oato.inaf.it/cme/
We present the status of the project, a sample of the results obtained, and a first
statistical analysis of some hundreds of classified events.
Author(s): Nicolina Chrysaphi
LPP, Sorbonne University, France
Abstract: The observed frequency-drift rate of solar radio bursts is used to obtain the speed with which the exciter of the radio photons is propagating through the heliosphere. Examples include the speed of CME-driven shocks and the speed of energetic electrons accelerated during solar flares. This exciter speed is often used to infer further values describing fundamental properties of either the local heliospheric environment or the exciter itself. However, relating the observed frequency-drift rate to the exciter speed requires the assumption that the drift rate is purely the result of the exciter’s motion. We demonstrate that this is not the case, presenting two additional contributors with often opposing impacts. We examine the balance between the different contributors and identify instances where the observations represent either an underestimation or an overestimation of the intrinsic exciter’s motion. Finally, we calculate the correction factor between the true and observed values, allowing us to infer the true speed of the exciters of radio emissions.
Author(s): Vratislav Krupar, Oksana Kruparova, Adam Szabo, Lynn B. Wilson III, Frantisek Nemec, Ondrej Santolik, Marc Pulupa, Karine Issautier, Stuart D. Bale, Milan Maksimovic
UMBC/GPHI & NASA/GSFC; UMBC/GPHI & NASA/GSFC; NASA/GSFC; NASA/GSFC; Faculty of Mathematics and Physics, Charles University; Institute of Atmospheric Physics of the Czech Academy of Sciences; University of California, Berkeley; Observatoire de Paris; University of California, Berkeley; Observatoire de Paris
Abstract: Type III radio bursts are generated by electron beams accelerated at reconnection sites in the corona. Our study, leveraging data from the Parker Solar Probe’s first 17 encounters, closely examines these bursts down to 13 solar radii. A key aspect of our analysis is the near-radial alignment (within 5°) of the Parker Solar Probe, STEREO-A, and Wind spacecraft relative to the Sun. This alignment enabled simultaneous observations of 52 bursts by STEREO-A and 27 by Wind, facilitating a detailed comparison of radial and longitudinal burst variations.
Our findings reveal no significant radial variations in electron beam speeds, radio fluxes, or exponential decay times for events occurring below 50 solar radii. However, closer to the Sun, we observed a decrease in beam speeds and radio fluxes. This suggests potential effects of radio beaming or changes in radio source sizes in this region.
These results emphasize the importance of considering spacecraft distance in multispacecraft observations for accurate radio burst analysis. A critical threshold of 50 solar radii emerges, beyond which beaming effects and changes in beam speeds and radio fluxes become significant. Additionally, the consistent decay times across varying radial distances indicate a stable trend extending from 13 solar radii into the inner heliosphere.
Our statistical results provide valuable insights into the propagation mechanisms of type III radio bursts, particularly highlighting the role of scattering near the radio source when the frequency matches the local electron plasma frequency.
Author(s): Gaetano Zimbardo, Bemporad A., Biondo R., Frassati F., Mancuso S., Mesoraca A., Nisticò G., Pagano P., Perri S., Prete G., Reale F., Susino R.
University of Calabria, Rende, Italy; INAF, Turin Astrophysical Observatory, Torino, Italy; INAF, Turin Astrophysical Observatory, Torino, Italy; INAF, Turin Astrophysical Observatory, Torino, Italy; INAF, Turin Astrophysical Observatory, Torino, Italy; University of Palermo, Palermo, Italy; University of Calabria, Rende, Italy; University of Palermo, Palermo, Italy, and INAF, Palermo Astronomical Observatory, Palermo, Italy; University of Calabria, Rende, Italy; University of Calabria, Rende, Italy; University of Palermo, Palermo, Italy, and INAF, Palermo Astronomical Observatory, Palermo, Italy; INAF, Turin Astrophysical Observatory, Torino, Italy
Abstract: Outstanding questions in space weather science are (i) how charged particles are accelerated up to high energies and (ii) how they are transported in magnetized environments. Among candidates for particle acceleration in the heliosphere there are shocks driven by eruptive phenomena in the solar corona, such as coronal mass ejections (CMEs). We started a new research project (*) whose main methods are (1) studying coronal shocks with both white light and UV coronagraphs (2) running magnetohydrodynamics (MHD) simulations of CME-driven shocks using RIMAP, a hybrid analytical-numerical technique to reconstruct the Parker spiral based on the PLUTO MHD code, and (3) analysing energetic particles measured in situ, also considering the measured magnetic turbulence levels in association with both diffusive and superdiffusive transport. Here, we show the results of applying these approaches to the fast CME event of September 5, 2022, which was measured in situ by Parker Solar Probe (PSP) and Solar Orbiter, and observed remotely by Stereo-A, SOHO and PSP.
We carry out the reconstruction of the CME by using SOHO/LASCO, STEREO-A/COR2, and PSP/WISPR data. The obtained CME parameters are used as an input for the RIMAP simulation, which also uses the in-situ solar wind data to describe more accurately the initial interplanetary conditions. Then we analyze the in-situ Solar Orbiter measurements to check the results of the RIMAP simulation and to study the CME-driven shock properties, the level of magnetic turbulence around the shock and energetic particle acceleration due to the shock. As preliminary results, we find that the energetic particles differential flux at Solar Orbiter has a spectral index harder than that predicted by diffusive shock acceleration for the measured compression ratio. The possible reasons for such a discrepancy are discussed.
(*) Project “Heliospheric shocks and space weather: from multispacecraft observations to numerical modeling”, funded by the Italian MUR within Next Generation EU, PRIN 2022294WNB.
Author(s): Nada AlHaddad, Noé Lugaz, Mitchell Berger, Florian Regnault, Wenyuan Yu, Bin Zhuang, Charles Farrugia
Space Science Center, UNH; Space Science Center, UNH; Exeter University; Space Science Center, UNH; Space Science Center, UNH; Space Science Center, UNH; Space Science Center, UNH
Abstract: Coronal Mass Ejections (CMEs) are highly complex magnetized plasma systems that pose significant challenges in understanding their three-dimensional structures and evolution. Historically, the heliospheric community has relied on single-spacecraft measurements and techniques like the “Highly Twisted Flux Rope” approximation to reconstruct CME magnetic configurations from one-dimensional time series data. However, these approaches fall short in fully capturing the intricate, multi-dimensional nature of CMEs’ magnetic fields and topologies. In order to allow for a more comprehensive understanding of CMEs’ structures, propagation, and aging and to move beyond the these limitations we need:
1. Dedicated multi-spacecraft measurements of CMEs: The necessity for dedicated multi-spacecraft missions designed to capture the variation scales of magnetic structures within CMEs is increasingly evident. Optimal spacecraft formations can provide the precise measurements needed to better understand the magnetic configuration and internal structures of CMEs.
2. New methods to extract three-dimensional magnetic field structures rather than two dimensional ones. Magnetic field structure of CMEs’ is a three dimensional one, and is continuously changing during CME evolution. Development of advanced techniques that are capable of accurately extracting the magnetic field structure is key for understanding CME and for the advancement of space weather.
3. Evolved understanding of CMEs’ structure driven by the continuous advancements of measurements and theory. Advancements made on both observational and theoretical fronts have to be reflected in the way the CMEs are constantly perceived.
In this work we a) explore analysis methods tailored explicitly for multi-spacecraft measurements using rare conjunctions. The results obtained by the analysis showcase the advancements that can be made with dedicated multi-spacecraft measurements, b) present a novel technique to directly extract the three-dimensional structure of CMEs., c) introduce a new perspective on CMEs compiling more than 40 year of CME studies.
Author(s): Cecilia Mac Cormack, Andreas Weiss, Fernando Carcaboso, Sanchita Pal, Tarik Salman, Teresa Nieves-Chinchilla, Jennifer Gannon, Delores Knipp, Tristen Wanner, Antti Pulkkinen
NASA Goddard Space Flight Center – Catholic University of America; NASA Goddard Space Flight Center; NASA Goddard Space Flight Center; NASA Goddard Space Flight Center; NASA Goddard Space Flight Center – George Mason University; NASA Goddard Space Flight Center; Computational Physics, Inc; Colorado Center for Astrodynamics Research – Space Weather Technology Research and Education Center; Embry-Riddle Aeronautical University; NASA Goddard Space Flight Center
Abstract: On May 12 2021, the first strong geomagnetic storm of solar cycle 25 was reported. This storm produced a Kp index of 7 and a drop in the Dst of around -60nT. The North American Electric Reliability Corporation (NERC) system observed the Geomagnetically Induced Current (GIC) response on ground based monitors. During the storm, the GIC spiked and then maintained elevated levels for 3-4 hours. This was observed over a large area of the US, from Kansas to the DC area. Understanding the GIC data, its relation with the space weather and the origin of the events is crucial to improve predictions and prevent several damages to the space and ground-based assets.
In this work we identified the solar source and the corresponding CME that leads to this strong geomagnetic storm. This CME arrives at Earth highly compressed, showing a sustained negative Bn component of the magnetic field that interacts with the magnetosphere and triggers the GIC response. We studied the origin of this compression by analyzing the early evolution of the CME and its interaction with the magnetic environment, and the later interaction with other simultaneous events and the Heliospheric Current Sheet (HCS).
Author(s): Andreas J. Weiss, Sanchita Pal, Teresa Nieves-Chinchilla, Christian Möstl
NASA Postdoctoral Program Fellowship, NASA Goddard Space Flight Center, Greenbelt, MD, USA; NASA Postdoctoral Program Fellowship, NASA Goddard Space Flight Center, Greenbelt, MD, USA; Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD, USA; Austrian Space Weather Office, GeoSphere Austria, Graz, Austria
Abstract: We present our latest results in attempting to understand and analyze the large-scale structure of ICMEs within the heliosphere. Recent events, as observed in situ by multiple spacecraft at varying locations, have strongly suggested that the large-scale structure of ICMEs can be significantly more complex than commonly assumed. Specifically, we have identified two occurrences where the ICME inclination, as locally inferred using cylindrical magnetic flux rope models, varies substantially by over 45 degrees.
To account for this, we have developed a novel ICME model, the “distorted magnetic flux rope” model. This model now allows us to reconstruct in situ observations for spacecraft that are up to 10 degrees apart in longitude. It also allows for the inclusion of arbitrary distorted cross-section shapes, to better reproduce asymmetric magnetic field profiles.
These initial results have important ramifications for the accuracy of
CME/ICME-related space weather predictions. The geomagnetic effectiveness of any ICME strongly depends on the Bz magnetic field component that is tied to the orientation of the embedded MFR. As such, the existence of a local MFR orientation insinuates that it may be significantly harder to predict the orientation and strength of the ICME magnetic field than is normally assumed.
Author(s): Junxiang Hu, Gang Li, Claudio Corti, Clayton Allison, M. Leila Mays
NASA GSFC / University of Alabama in Huntsville; University of Alabama in Huntsville; NASA GSFC CCMC / USRA / University of Hawaii; NASA JSC SRAG / Leidos; NASA GSFC CCMC
Abstract: Solar Energetic Particles (SEP) events, especially the gradual ones associated with CME-driven shocks, are the most hazardous space weather events in the inner heliosphere. Predicting SEP intensities in real time before their impact on Earth and other observatories is one of the critical missions in space weather forecasting. Recently, we utilized the improved Particle Acceleration and Transport in the Heliosphere (iPATH) model to design a physics-based, fully automated real-time SEP forecasting/nowcasting pipeline. This pipeline is now operational at NASA’s Community Coordinated Modeling Center (CCMC) and SEP Scoreboard, producing SEP time-intensity profiles at multiple observer locations. We will discuss how we set up periodic background solar wind and event-triggered CME simulations using input parameters retrieved from real-time databases. We will present recent progress in model development, including a study on the flare-CME relationship to advance prediction time. We will also show the validation results for this pipeline using various historical events as part of the SEPVAL (SEP Model Validation Working Meeting) effort.
Author(s): Giuseppe Prete, Antonio Esteban Niemela, Stefaan Poedts, Gaetano ZImbardo, Stefano Cicalo’, Maria Federica Marcucci, Monica Laurenza, Mirko Stumpo, Simone Landi, Lorenzo Provinciali, Davide Monferrini, Davide Calcagno, Valerio Di Tana, Roger Walker
Department of Physics University of Calabria; Centre for Mathematical Plasma Astrophysics, Dept. of Mathematics, KU Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium; Centre for Mathematical Plasma Astrophysics, Dept. of Mathematics, KU Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium – Institute of Physics, University of Maria Curie-Skłodowska, Pl. M. Curie-Skłodowska 5, 20-031 Lublin, Poland; Department of Physics University of Calabria; SpaceDys, Pisa Italia; INAF, IAPS, Roma, Italy; INAF, IAPS, Roma, Italy; INAF, IAPS, Roma, Italy; Università degli Studi di Firenze, Firenze, Italy; ARGOTEC, Torino, Italy; ARGOTEC, Torino, Italy; ARGOTEC, Torino, Italy; ARGOTEC, Torino, Italy; ESA-ESTEC, Noordwijk, Netherlands
Abstract: Space missions play a key role in predicting natural hazards like Coronal Mass Ejections (CMEs) and high fluxes of solar energetic particles that hit the Earth. In this work we are going to describe a new space mission designed to the study of these extreme pheonemena. The name of the space mission is HEliospheric pioNeer for solar and interplanetary threats defeNce (HENON) and its aim of the mission is to improve the forecasting capabilities of the Space Weather hazards such as SEPs/CMEs events and geoffective interplanetary disturbences. HENON is made by a CubeSat orbiting on a Distant Retrograde Orbit (DRO) of the Sun-Earth system, and this DRO is chosen such as that spacecraft will be at 0.1 AU upstream of the Earth for a very long period. The mission is scheduled to launch in 2026. In order to have an idea on what the mission is capable of, we use numerical simulations to reproduce the behavior of the satellite when a Sun’s extreme phenomena hit the Earth. We use the 3D-MHD numerical code EUHFORIA. We inserted the possible trajectories of the Henon spacecraft in EUHFORIA and we simulated the evolution of CMEs varying the initial parameters of the code. We determined the Dst index and the VBz parameter that allow us to understand if a specific event can be dangerous for the environement around the Earth or not. In this way we make a forecasting analysis in order to understand what are the events potentially dangerous for space missions, astronaut missions, GPS systems and so on.
HENON is in the C1 study phase that is being developed in the framework of the ESA General Support Technology Program (GSTP). HENON is funded by the Italian Space Agency as part of the ALCOR programme.
Author(s): Laura Rodríguez García, Raúl Gómez-Herrero, Nina Dresing, Laura Balmaceda, Erika Palmerio, Athanasios Kouloumvakos, Francisco Espinosa Lara, Mario Roco, Christian Palmroos, Immanuel Jebaraj, Alexander Warmuth, Georgios Nicolau, Ignacio Cernuda, Teresa Nieves-Chinchilla, Annamaria Fedeli, Christina Lee, Christina Cohen, Jingnan Guo, Timo Laitinen, Glen Mason, George Ho, Olga Malandraki, Javier Rodríguez-Pacheco
ESA; Universidad de Alcalá; University of Turku; George Mason University; Predictive Science; The Johns Hopkins University; Universidad de Alcalá; Universidad de Alcalá; University of Turku; University of Turku; Leibniz-Institut für Astrophysik Potsdam (AIP); Mullard Space Science Laboratory; Universidad de Alcalá; NASA; University of Turku; Space Sciences Laboratory; California Institute of Technology; Deep Space Exploration Laboratory/School of Earth and Space Sciences; Jeremiah Horrocks Institute, University Central Lancashire; The Johns Hopkins University Applied Physics Laboratory; Southwest Research Institute; National Observatory of Athens; Universidad de Alcalá
Abstract: On 2022 January 20, the Energetic Particle Detector (EPD) on board Solar Orbiter measured a solar energetic particle (SEP) event showing unusual first arriving particles from the anti-Sun direction. Near-Earth spacecraft separated 17° in longitude to the west from Solar Orbiter measured classic antisunward-directed fluxes. STEREO-A and MAVEN, separated 18° to the east and 143° to the west from Solar Orbiter respectively, also observed the event, suggesting that particles spread over nearly 160° in the heliosphere. The energetic particles reached 3 MeV and 100 MeV energies for electrons and protons, respectively. Our goal is to investigate how SEPs are accelerated and transported to Solar Orbiter and near-Earth spacecraft, as well as to examine the influence of a magnetic cloud (MC) present in the heliosphere at the time of the event onset in the propagation of the energetic particles. Particle observations at Solar Orbiter are used to probe the magnetic structure inside the MC.
The SEP event is related to a M5.5 flare and a fast CME-driven shock of ∼1433 km/s which injected particles within and outside an MC. The timing and anisotropies of the particles arriving to Solar Orbiter strongly suggest that the particles were injected along the longest (western) leg of an interplanetary CME still connected to the Sun at the time of the release of the particles. The determined electron path length is around 30% longer than the estimate length of the loop leg of the MC itself (based on the GCS model) consistent with a low number of field line rotations.
Author(s): Love karya
Acharya institute of sciences
Abstract: The heliosphere often experiences the CMEs (Coronal Mass ejections). This magnificent phenomena are associated as sunspots (accounted by sunspot number SSN), geomagnetic storms (accounted by disturbed storm index Dst), Solar flares (Categorised as A, B, C, S, X class flares). Particles of high energy are also fluxed out which possess intense magnetic properties. They are usually ejected at very high speeds. In case if they are earth attracted, they ram up with earth’s magnetosphere at very high speeds which may vary from a few tens of km/s to thousands of km/s. In our research we have threshold the CME’s which have a minimum speed of 350 Km/s to understand their relation with SSN and have found their strong correlation of 0.97 during the solar cycle of 24.
Author(s): Valeriy Tenishev
Marshall Space Flight Center
Abstract: Solar energetic particles (SEPs), high-energy particles emitted by the Sun, present significant risks to space missions, particularly those beyond Earth’s protective magnetosphere. Gaining insight into their behavior within the heliosphere and Earth’s magnetosphere is crucial for ensuring space exploration endeavors’ safety and operational integrity. This study examines the role of pitch angle scattering—where a particle’s velocity vector alters relative to the magnetic field due to interactions with magnetic fluctuations—on the decline phase of SEP events. By solving the focused transport equation, the research models SEP propagation along magnetic field lines, extending these lines to a distance of up to 5 Astronomical Units (AU), thus providing an understanding of SEP behavior even in regions far from the Sun.
Incorporating pitch angle scattering effects at these extended distances is essential for a comprehensive understanding of SEP event decay dynamics. This modeling of SEPs is further integrated with simulations of other critical space phenomena, including the solar wind, interplanetary magnetic field, and Alfvén wave turbulence. This presentation details the modeling techniques employed in this research and explores the impact of pitch angle scattering at various heliocentric distances on the SEP events’ decay phase dynamics.
Author(s): Seve Nyberg, Rami Vainio, Laura Vuorinen, Alexandr Afanasiev
University of Turku; University of Turku; University of Turku; Univeristy of Turku
Abstract: Solar eruptions, i.e., flares and coronal mass ejections (CMEs), are associated with energetic electron events, but details of the acceleration and transport mechanisms are still under debate. Previous observational research (e.g., Dresing et al. 2022, ApJ, doi:10.3847/2041-8213/ac4ca7) has reveled that coronal shocks driven by CMEs are a strong candidate to account for relativistic electrons in large gradual energetic particle events. It is, however, still not clear how shocks accelerate electrons.
We explore how electrons interact with shock waves under the assumptions of stochastic shock drift acceleration (SSDA) utilizing numerical simulations. SSDA considers the interaction of energetic electrons with the shock wave including the effect of micro-turbulence inside the shock ramp while still considering the scattering conditions in the ambient medium to be weak, i.e., insufficient for the diffusive shock acceleration mechanism to operate efficiently. We probe the shock-wave parameter space, i.e., shock speed, shock obliquity, shock thickness, and plasma density upstream of the shock, and determine electron spectra and cutoff energies resulting form SSDA. With suitable parameters, the SSDA model is able to accelerate thermal electrons to relativistic energies and, additionally, able to produce an electron beam upstream of the shock wave, a requirement for the generation of plasma emission seen in type II radio bursts associated with coronal shocks.
This poster presents the results of the simulations on electron acceleration and transport within shock waves, contributing to our understanding of solar coronal phenomena and their practical applications in space weather forecasting.
This study has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement No 101134999 (SOLER). The presentation reflects only the authors’ view and the European Commission is not responsible for any use that may be made of the information it contains.
Author(s): Emanuele Cazzola, Dominique Fontaine, Philippe Savoini
Laboratoire de Physique des Plasmas (LPP), CNRS, Observatoire de Paris, Sorbonne Université, Université Paris-Saclay, École polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France; Laboratoire de Physique des Plasmas (LPP), CNRS, Observatoire de Paris, Sorbonne Université, Université Paris-Saclay, École polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France; Laboratoire de Physique des Plasmas (LPP), CNRS, Observatoire de Paris, Sorbonne Université, Université Paris-Saclay, École polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France
Abstract: Interplanetary shocks are ubiquitous in the solar system and can originate from different sources, such as, e.g., high-speed streams, coronal mass ejections or co-rotating interaction regions.
Here, we present a self-consistent simulation of the interplanetary shocks propagation as developed from a mere difference in the velocity amplitude in the solar wind at typically 1 AU. Together with the shock itself, and just downstream of it, a turbulent region progressively forms and grows in a more complex structure than in the pristine solar wind. Significant variations in some important quantities, such as the velocity and magnetic field components, are detected and found to be in line with satellite observations of solar events including shock waves.
We additionally investigate the impact of the interplanetary shock on the Earth’s bow-shock, which is the first met boundary of the terrestrial environment. As it propagates throughout, we show that it progressively modifies the bow-shock’s shape and the structure of the regions nearby. In particular, we show that it causes a temporal variation of the local normal-based kinetic phenomena, such as the foreshock region.
Author(s): James Chen
George Mason University and US Naval Research Laboratory
Abstract: As coronal mass ejections (CMEs) erupt, they are driven outward by the Lorentz
force and interact with the ambient coronal and solar wind (SW) medium via
drag, expending magnetic energy. The dynamics of a CME are determined by the
evolution of the magnetic field and Lorentz force, which in turn depends on the
inductance of the expanding magnetic structure and momentum coupling. In this
work, we model CMEs as 3D magnetic flux ropes and use the Erupting Flux Rope
(EFR) model (Chen 1996) to calculate the magnetic field and forces of evolving
CME. This model has been extensively validated using observed CME
trajectories, but the evolution of the magnetic field has only been tested at
1 AU (Kunkel and Chen 2010). With in situ magnetometer data from a number of
near-sun satellites, we are now able to track individual CME structures and
test the evolution of CME magnetic fields predicted by the EFR theory at a
number of locations when fortuitous alignment occurs. We identified an event
with CME trajectory data from STEREO-A/B, magnetic field data from MESSENGER
near Mercury, and WIND magnetometer data at the L1 Lagrange point. The source
region was observable in detail by SDO in a geosynchronous orbit at Earth.
Another quantity predicted by EFR but hitherto unverified is the SW density
Nsw and speed Vsw actually encountered by a given CME as it expands. In the
absence of such SW data except at 1 AU, we appeal to the Global 3D MHD
(G3DMHD) simulation model (Wu et al. 2020). We use this model to simulate the
undisturbed SW in 3D based on the observed photospheric synoptic magnetogram
data. The SW profile predicted by EFR and that predicted by G3DMHD are
compared. We demonstrate that the theoretical EFR model is able to replicate
(1) the trajectory observed by STEREO and (2) magnetic field observed in situ
by MESSENGER and WIND, and that (3) the calculated SW profile is consistent
with the output of G3DMHD. The EFR model thus provides a basis for developing
a faster-than-real-time forecasting method for severe space weather phenomena
caused by the magnetic field of CME ejecta.
Chen, J. 1996, JGR, 101, 27499.
Kunkel, V., and Chen, J. 2010, ApJ Lett, 715, L80.
Wu, C.-C. et al. 2020, Sol. Phys., 295, No. 25.
Author(s): Ian G. Richardson, Tycho T. von Rosenvinge, O. Chris St. Cyr, David Lario, J. Grant Mitchell
University of Maryland/NASA GSFC; GSFC, retired; GSFC, retired; GSFC; GSFC
Abstract: The High Energy Telescopes (HETs) (von Rosenvinge et al., 2008) on the STEREO A and B spacecraft make observations of 0.7-4 MeV electrons and 13.6-100 MeV protons. Nearly 500 individual solar energetic particle (SEP) events that include 25 MeV protons and exceed the instrumental thresholds have been detected at either the STEREOs and/or near-Earth spacecraft since launch in October 2006. STEREO A completed a solar orbit (relative to Earth) in August 2023; contact with STEREO B was lost in October 2014. We summarize the properties of these events, which together provide around 1000 observations of SEP events close to the ecliptic at a wide range in longitude with respect to the associated flare. Although the associated solar event can usually be identified unambiguously using a combination of in situ and remote sensing observations, in a small number of events, this is more challenging or the event has some interesting features, and several cases will be illustrated. Observations from other spacecraft, including Solar Orbiter and Parker Solar Probe in the inner heliosphere can also provide additional insight.
Author(s): Zheyi Ding, Gang Li, Nicolas Wijsen, Stefaan Poedts, Shuo Yao
Kiel University (CAU); General Linear Space Plasma Lab; KU Leuven; KU Leuven; China University of Geosciences (Beijing)
Abstract: We examine the influence of perpendicular diffusion on the energetic ion spectrum within corotating interaction regions (CIRs), with a particular emphasis on its dependence on the mass-to-charge (A/Q) ratio. A synthetic CIR is simulated using the EUropean Heliospheric FORecasting Information Asset (EUHFORIA), and the subsequent ion acceleration and transport are modeled by solving the focused transport equation, which includes both parallel and perpendicular diffusion. Our findings demonstrate significant differences in the ion spectra between scenarios that include and exclude perpendicular diffusion. Without perpendicular diffusion, ion spectra near CIRs exhibit a strong (A/Q)^α dependence, where α varies with the turbulence spectral index, consistent with theoretical expectations. In contrast, the presence of perpendicular diffusion, which features a weak A/Q dependence, results in similar spectra across different ion species, in qualitative agreement with observations of energetic particles in CIRs.
Author(s): Roger Prat, Àngels Aran, Nicolas Wijsen, Stefaan Poedts, Sigiava Aminalragia, Ingmar Sandberg, Pier Jiggens
Universitat de Barcelona; Universitat de Barcelona; KU Leuven; KU Leuven; Space Applications & Research Consultancy; Space Applications & Research Consultancy; ESA
Abstract: Solar eruptive events may accelerate energetic electrons that usually precede the arrival of the proton and ion components during Solar Energetic Particle (SEP) events. These latter species have been much more studied in particle radiation environment models than electrons. Such electron populations can reach energies of at least several hundred keV (10 keV to > 1 MeV) with differential flux values of several orders of magnitudeabove background intensity levels. These characteristics make them important for space weather safety considerations as they can have significant effects such as surface charging and surface erosion. These considerations become even more important for missions of long duration particularly outside the Earth’s magnetosphere.
The study we present is embedded within the scope of the ESA’s FIRESPELL project. One of the objectives of this project is to extend the application of the SAPPHIRE-2S particle radiation model to electrons, in the energy range from 50 keV to 4 MeV and extending it for interplanetary missions travelling within 0.2 au to 10 au from the Sun. Using data from IMP-8/CPME, ACE/EPAM and SOHO/COSTEP a standardized dataset of electron events has been generated spanning from 1974 to 2017. From this dataset an event list of 401 electrons events was generated.
We aim to reproduce this observed (at 1 au) electron event list to other radial distances by means of modelling the peak intensity and fluence radial dependence for several reference events, following the work performed for proton events in the SEPEM project (sepem.eu). To this end, we have used this dataset and event list to perform an observational study in order to classify the solar energetic electron events (SEE) according to two parameters: the heliolongitude of the parent solar eruption and the time elapsed from the occurrence of the solar event until the peak intensity is reached. We have divided the events into 5 categories:
Eastern events, those events associated with solar eruptions from heliolongitudes eastern than E35; Central meridian events, those events originated from heliolongitudes within E35 and W25; and events from western longitudes. The western cases are then split in three categories: Impulsive events, for which the peak intensity is reached within the first 4 hours; Rounded impulsive events, for which the peak occurs between 4 to 14 hours, and West events, for which the peak is obtained at later times. We present here the events classification, the selected cases for the western events, and the results from simulations of electron transport during Impulsive, Rounded Impulsive and West events, offering insights into the behavior and transport of electrons in interplanetary space.
FIRESPELL is a project funded by ESA (Contract No. 4000142510/23/NL/CRS).
Author(s): Katya Georgieva, Boian Kirov, Simeon Asenovski
Space Research and Technology Institute at the Bulgarian Academy of Sciences; Space Research and Technology Institute at the Bulgarian Academy of Sciences; Space Research and Technology Institute at the Bulgarian Academy of Sciences
Abstract: Coronal mass ejections (CMEs) are drivers of the most powerful geomagnetic storms. CMEs are related to solar magnetic fields which can grow and become more twisted and complex, until they become unstable and release the stored magnetic energy as CMEs. Sunspots serve as visible markers of the Sun’s magnetic activity which peaks during the maximum of the 11-year solar cycle, so it can be expected that more sunspots/stronger magnetic fields would lead to more CMEs. Indeed, the occurrence frequency of CMEs varies by an order of magnitude over the sunspot cycle and tends to follow sunspot numbers in both phase and amplitude.
CMEs have been regularly detected by LASCO/SOHO since 1996 (since sunspot cycle 23) – a period supposedly coinciding with the end of the last centennial (Gleissberg) solar activity cycle and the minimum between it and the beginning next Gleissberg cycle. These observations revealed that the relation between the number of sunspots and the number of CMEs is not linear: First, in cycle 23 the number of CMEs didn’t follow the decline in the sunspot number on the descending phase of the cycle, but instead depicted a broad plateau. Second, though the number of sunspots was much lower in cycle 24 than in cycle 23, the number of CMEs was much higher, a tendency which seems to persist during the ongoing cycle 25. Several possible explanations have been proposed for this non-linearity.
Here we examine the ratio between the number of CMEs and the sunspot number since the previous Gleissberg minimum (19/20 centuries) based on both instrumental observations and proxy estimates of the number of CMEs. We then compare this ratio with the magnetic fields in sunspots as a proxy for the magnetic fields in active regions from where CMEs originate. We find that the ratio between the number of CMEs and the sunspot numbers is pretty constant for a wide range of sunspot magnetic fields, down to a certain threshold below which with decreasing magnetic field the occurrence rate of CMEs quickly grows. This is a confirmation of one of the proposed explanations for the recently observed non-linearity, namely that strong magnetic fields in CME source regions are constraints for CME initiation, because a CME must first overcome the background magnetic field before it can erupt. With weak magnetic fields of active regions, the constraint on the background magnetic fields for the eruptive events is also weak, which makes it easier for the CMEs to escape outward, and leads to a bigger number of CMEs, though slower and weaker. Finally, we elaborate on the long-term variations of the sunspot/active regions magnetic fields and the related ratio between the CMEs and sunspot numbers.
Author(s): Botakoz Seifullina, Olga Kryakunova, Anatoly Belov, Artem Abunin, Maria Abunina, Irina Tsepakina, Nikolay Nikolayevskiy
Institute of Ionosphere, Almaty, Kazakhstan; Institute of Ionosphere, Almaty, Kazakhstan; Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Moscow, Russia; Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Moscow, Russia; Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Moscow, Russia; Institute of Ionosphere, Almaty, Kazakhstan; Institute of Ionosphere, Almaty, Kazakhstan
Abstract: The Forbush effect refers to changes in the density and anisotropy of cosmic rays due to large-scale disturbances in the solar wind. These effects are closely linked to geomagnetic activity, both resulting from interplanetary disturbances. This study examines Forbush effects triggered by sporadic interplanetary medium disturbances caused by coronal mass ejections (CMEs) associated with solar flares. A catalogue of Forbush events from 1995 to 2023, related to solar flares accompanied by CMEs, has been compiled. For each CME-related event, interplanetary conditions were analyzed using satellite data, solar sources were identified, and the density and vector anisotropy of galactic cosmic rays (GCR) beyond the magnetosphere were calculated using the Global Survey Method (GSM). The study identifies patterns in the variations of GCR density and vector anisotropy as well as determining the maximum values of GCR density and vector anisotropy.
Author(s): Myrthe Flossie, Nicolas Wijsen, Anwesha Maharana, Luis Linan, Tinatin Baratashvili, Stefaan Poedts
KU Leuven; KU Leuven; KU Leuven; KU Leuven; KU Leuven; KU Leuven, University of Maria Curie-Skłodowska
Abstract: SEP modelling with an advanced flux-rope CME model
M. Flossie 1, N. Wijsen 1, A. Maharana 1, L. Linan 1, T. Baratashvili 1, S. Poedts 1,2
1 CmPA/Dept. of Mathematics, KU Leuven
2 University of Maria Curie-Skłodowska, Lublin, Poland
The newest CME models introduced in the EUHFORIA solar wind software, developed at KU Leuven, include the computationally expensive Flux Rope in 3D (FRi3D) model. This CME model provides a more realistic description of the magnetic field structure of a CME since it is not radially symmetric and does not have a spherical shape like older models. Due to its separate legs, it allows for a more realistic prediction when a CME hits Earth with its flank.
However, these novel flux rope CME models are computationally expensive. To address this, an optimisation method has been developed to speed up the calculation of the FRi3D model by storing the 3D structure of the CME in a separate datacube that can be reused in various solar wind predictions. This method, called the datacube method, simplifies the calculations and reduces computation time by a factor of five in low resolution. This optimization also makes it possible to obtain high-resolution runs of the FRi3D model, which were previously difficult to achieve due to high computation times. Since these novel flux rope CME models provide more realistic representations of CMEs, whether they yield more accurate results regarding simulations of Solar Energetic Particles (SEPs) is being investigated. For this purpose, high-resolution solar wind predictions are required to serve as input values for simulations that include SEPs, for which the PARADISE software is utilized to solve the Focused Transport Equation (FTE).
Using PARADISE, electrons are injected into the legs of the simulated CME, which serve as probes for its three-dimensional structure as electrons flow along the magnetic field lines of the flux rope. As a result, bidirectional electrons are simulated at the front of the CME, appearing when electrons are injected into both legs and inside one leg. This observation is referred to as counterstreaming electron beams and corresponds to observations at Earth during the passage of a CME, proving the validity of the FRi3D CME model. Additionally, by altering the mean free path of the simulated electrons, simulations for which the value of the mean free path is around 5-10 AU provide the most accurate results compared to in-situ observations. When enabling cross-field diffusion, which allows for particle escape from the flux rope, counterstreaming electrons are observed before the actual arrival of the CME.
This project (Open SESAME) has received funding from the European Research Council Executive Agency (ERCEA) under the ERC-AdG agreement No 101141362.
Author(s): Edmund Serpell
Telespazio Germany
Abstract: Gaia is the European Space Agency’s astrometry mission that has been operating at the second sun-earth Lagrange point since 2014. During its time in space, Gaia has experienced almost a complete solar Schwabe period, from the maximum of cycle 24 to the maximum of cycle 25. At the L2 position, Gaia has been directly exposed to the energetic charged particles of the galactic cosmic ray background and the solar wind. Additionally, at the time of solar flares, Gaia has been bombarded by solar x-rays.
Gaia has been routinely measuring the charged particle environment by counting individual ionisation tracks that have occurred in the CCDs of the focal plane. Recently, it has been observed that photon signals from solar x-ray flares are also visible in the particle data, if the flare occurred at a time when the spacecraft attitude was favourable for such a measurement.
In this poster, a textbook example is presented of a Gaia measurement of a solar x-ray flare with magnitude X2.5 that occurred on 16th February 2024. The Gaia measurement of the photon signal followed by the charged particle signal from this event will be shown. Although charged particles can penetrate to the CCDs, if they are sufficiently energetic, there is never a direct light-path from the sun to the Gaia focal plane, so the photon signal is due to secondary photons emitted by fluorescence due to ionisation of the spacecraft structure.