SWR3 – Inner Magnetospheric Dynamics and Coupling Processes

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SWR3.1 Tue 5/11 17:30-18:30, room C2A – Mondego

Author(s): Dedong Wang

Gfz German Research Centre For Geosciences

Abstract: The magnetosphere is a natural plasma laboratory. Radiation belts and ring current in the magnetosphere abound in high energy particles. The energetic electrons in the Earth’s radiation belts and ring current can be hazardous to Earth-orbiting satellites and astronauts in space. Numerous space systems crucial to modern society operate within this region. The fluxes of the radiation belt and ring current electrons are very dynamic, which is not fully understood due to the delicate balance between various acceleration and loss processes. Wave-particle interactions are believed to play a crucial role in the acceleration and loss of these particles.

To quantify the effect of different waves on the dynamics of radiation belt electrons, comprehensive wave models are needed. Scientists in our community have made great achievements in developing wave models. However, the space coverage of most of these wave models is not sufficient due to the orbit limit of satellites, in particular, at higher geomagnetic latitudes. In the project “Waves in the Inner Magnetosphere and their Effects on Radiation Belt Electrons (WIRE)” recently funded by the European Research Council Consolidator Grant, combining state-of-the-art measurements from multiple satellites, comprehensive wave models will be developed. We are improving our sophisticated physics-based radiation belt and ring current electron dynamic model by using most advanced wave models and calculating diffusion coefficients using more realistic background magnetic field and cold plasma density models. Furthermore, fundamental acceleration and loss of energetic electrons caused by different waves in the Earth’s radiation belts will be quantified. We systematically validate simulation results against satellite measurements to understand the competition between acceleration and loss caused by various mechanisms.

All these improvements will be critically important for answering the overarching scientific question: Why do the Earth’s radiation belts respond differently to geomagnetic storms which have approximately the same intensity? The knowledge gained in this project can be useful for basic plasma physics and astronomy physics because similar fundamental processes exist. This project will help to understand, to predict, and to specify the hazardous space environment.

Author(s): János Lichtenberger, Tamás Bozóki, Nikolai Lehtinen, Lilla Murár-Juhász, Dávid Koronczay, Attila Buzás, Péter Steinbach, Szilárd Pásztor, Miroslav Hanzelka, Mark Clilverd, Craig Rodger, Stefan Lotz

Department of Geophysics and Space Sciences, Eötvös University; HUN-REN Institute of Earth Physics and Space Science; Birkeland Centre for Space Science, University of Bergen; HUN-REN-ELTE Space Research Group; HUN-REN-ELTE Space Research Group; HUN-REN-ELTE Space Research Group; HUN-REN-ELTE Space Research Group; Department of Geophysics and Space Sciences, Eötvös University; Institute of Atmospheric Physics; British Antarctic Survey,; University of Otago; SANSA Space Science

Abstract: Energetic electrons in the outer radiation belt can undergo gyroresonant interaction with various magnetospheric wave modes including whistler-mode VLF chorus outside the plasmasphere and whistler-mode hiss inside the plasmasphere. The result of this process can be the  energization and precipitation of the energetic electrons by pitch angle or energy scattering. The calculation of diffusion coefficients requires the wave power of these waves at the wave-particle interaction region. This is available only for certain locations and times from in-situ measurements of recent science missions (Van Allen Probes, Arase missions) and not in real-time. Whistler mode waves below the half of the equatorial gyrofrequency can propagate in ducted/field aligned mode along the magnetic field line to the ground,
The  wave power measured on the ground by Automatic Whistler Detector and Analyzer Network (AWDANet, Lichtenberger et al., 2008, JGR) is used to estimate the in-situ wave power combining propagation models, such as ducted propagation model in the magnetosphere  and the Stanford Full Wave Model ( FWM, Lehtinen and Inan , 2009, GRL) for trans- and subionospheric propagation.
The models were calibrated and validated by chorus, hiss and VLF transmitter data measured by EMFISIS instrument on Van Allen Probes.
The estimated wave power is used in Forecast of Actionable Radiation Belt Scenarios (FARBES, https://farbes.eu)  Horizon Europe project in Salammbo Radiation Belt model upgraded to use ground-based drivers.

Author(s): Karen J C Ferreira, Lívia Ribeiro Alves, Lígia Alves da Silva, José Paulo Marchezi, Vinícius Deggeroni

National Institute for Space Research; National Institute for Space Research; National Institute for Space Research; China-Brazil Joint Laboratory; University of New Hampshire; National Institute for Space Research

Abstract: Interplanetary Coronal Mass Ejections (ICMEs) significantly impact Earth’s magnetosphere, particularly through their sheath regions, which trigger various plasma waves and affect the outer radiation belt dynamics. This study examines the mechanisms driving electron flux dropout and maintenance during a prolonged 20-hour sheath region associated with an ICME event on October 2nd, 2013. The objective is to elucidate the characteristics of this extended-duration sheath and explore how its temporal evolution intersects with wave activity, thereby influencing the outer radiation belt dynamics. During the initial 6 hours of the sheath region, heightened wave activity was driven by peaks in dynamic pressure, a southward-oriented B_z component, high levels of magnetospheric compression, and discrete structures in the Interplanetary Magnetic Field (IMF). Electromagnetic Ion Cyclotron (EMIC) waves induced rapid electron flux depletion, leading to a one-order-of-magnitude loss within 15 minutes for polar pitch angles. Additionally, Chorus waves competed with EMIC waves in accelerating electrons. Conversely, equatorial pitch angles experienced a slower dropout, spanning one order of magnitude over 30 minutes, attributed to magnetopause compressions and releases coupled with Ultra Low Frequency (ULF) waves. This process drove inward and outward radial diffusion, alongside magnetopause shadowing effects. As a result, a dropout of one order of magnitude was observed, reaching 3.5 R_E. After the initial 6-hour period, the sheath region stabilized, with wave activity diminishing, maintaining low flux levels until the arrival of the magnetic cloud. These results highlight the nuanced temporal dynamics of sheath region properties and their implications for magnetospheric dynamics and outer radiation belt variability, shedding light on fundamental processes in space weather. This study provides a detailed analysis of the temporal evolution of sheath regions associated with ICMEs and their impact on the outer radiation belt. By examining the interplay between wave activity and electron flux dropout mechanisms, we gain a deeper understanding of the complex interactions that govern space weather phenomena. These findings underscore the importance of considering both rapid and gradual processes in the analysis of magnetospheric responses to ICME events, offering valuable insights for future research and space weather forecasting.

Author(s): Alexandra Triantopoulou, Christos Katsavrias, Ioannis A. Daglis

National and Kapodistrian University of Athens; National and Kapodistrian University of Athens; National and Kapodistrian University of Athens

Abstract: The variability of the lower energy electron fluxes of the outer Van Allen belt is crucial for the inner magnetosphere dynamics and satellite operations. Especially, the subrelativistic population is important for two main reasons: first, source and seed electrons act as a reservoir that can be accelerated to relativistic energies; second, they are responsible for surface and internal charging effects on satellites. This study explores the dynamics of these electrons, ranging from tens to hundreds of keV.
Using 9 years of data (2011-2019) from the THEMIS-A, D and E missions, spanning Solar Cycle 24, we analyzed long-term differential electron flux across nine energy channels (30 – 800 keV). These energy channels represent seed (10 – 100 keV), source (100 – 300 keV), and relativistic electrons (>500 keV). We correlated these fluxes with various magnetospheric and solar wind parameters from NASA’s Space Physics Data Facility and OMNI database, using a comprehensive binning process. We also utilized the Epsilon parameter, Half-wave rectifier, and Newell’s function, which have been shown to predict how the solar wind interacts with the magnetosphere. In addition, we conducted a cross-calibration with fluxes recorded by GOES 13 and 15.
This research provides key insights for predicting electron variability and mitigating risks to satellite systems. We will discuss the resulting features and their implications for predicting electron variability.

SWR3.2 Thu 7/11 14:15-15:15, room C2A – Mondego

Author(s): Richard Horne, Thomas Daggitt, Nigel Meredith, Sarah Glauert, Xu Liu, Lunjin Chen

British Antarctic Survey; British antarctic Survey; British Antarctic Survey; British Antarctic Survey; University of Texas at Dallas; University of Texas at Dallas

Abstract: The plasma density is one of the most fundamental quantities of any plasma yet measuring it in space is exceptionally difficult when the density is low.  Measurements from particle detectors are contaminated by spacecraft photoelectrons and methods using plasma wave emissions are hampered by natural plasma instabilities which dominate the wave spectrum.   Here we present a new method which calculates the density from magnetosonic waves near the lower hybrid resonance frequency.  The method works most effectively when the ratio of the electron plasma to cyclotron frequency is less than 3.5.  The method provides a lower bound on the plasma density.   Using the new method, we show that wave acceleration of electrons to relativistic energies is increased by orders of magnitude.  The method enables years of satellite data to be re-analysed for the Earth and the effectiveness of wave acceleration at the Earth, Jupiter and Saturn to be re-assessed.

Author(s): Aleksandr Rubtsov, Masahito Nose, Ayako Matsuoka, Yoshiya Kasahara, Atsushi Kumamoto, Fuminori Tsuchiya, Tomoaki Hori, Mariko Teramoto, Iku Shinohara, Yoshizumi Miyoshi

Institute of Solar-Terrestrial Physics SB RAS, Irkutsk, Russia; Nagoya City University, Nagoya, Japan; Kyoto University, Kyoto, Japan; Kanazawa University, Kanazawa, Japan; Tohoku University, Sendai, Japan; Tohoku University, Sendai, Japan; Nagoya University, Nagoya, Japan; Kyushu Institute of Technology, Kitakyusyu, Japan; Japan Aerospace Exploration Agency, Sagamihara, Japan; Nagoya University, Nagoya, Japan

Abstract: We present the spatial distribution of Pc4 and Pc5 ULF waves (45–600 s period) based on Arase satellite data from 2017 to 2020. The Arase three times covered the whole magnetosphere and geomagnetic latitudes from −40 to 40 degrees. We analyzed the occurrence rate and wave frequency of twelve thousand waves in the dataset, divided into toroidal, poloidal and compressional waves according to the direction of the largest amplitude oscillations. Some key features of the Alfvén waves were found for toroidal and poloidal waves, while some unexpected details are present as well. First, we found no clear separation between waves of all three kinds of polarization. The most common is mixed polarization, when poloidal and toroidal wave amplitudes are almost the same. Compressional waves always have significant transverse, mostly poloidal, component. Nevertheless, waves of different polarizations have different spatial distributions, raising the question of the role of polarization change in time and/or space. Second, we revealed the dependence of the spatial distribution of poloidal and toroidal waves on the plasmapause location. These waves occur mostly outside the plasmasphere with a 1–2 RE gap from the plasmapause. This dependence is clear for dusk and night sector waves, and we suggest this is due to the storm/substorm source of them, while day and dawn sector waves generated by sources from the solar wind are not affected. The results of the present study advance our knowledge of wave-particle interactions in the magnetosphere that directly affect radiation belt electrons and ring current ions.
The work was financially supported by the Russian Science Foundation under Grant 22-77-10032.

Author(s): Xinlin Li

University of Colorado Boulder

Abstract: Colorado Student Space Weather Experiment (CSSWE) CubeSat, carrying Relativistic Electron and Proton Telescope integrated little experiment (REPTile) to measure 0.5 to >3.8 MeV electrons and 8-40 MeV protons, operated for over two years, 2012-2014, in low Earth orbit (LEO), and shed new light on the dynamics of energetic particles in the near-Earth environment. There have been 29 peer-reviewed publications, including two in Nature, and five Ph.D. dissertations associated with CSSWE. Another 3U CubeSat mission: Colorado Inner Radiation Belt Electron Experiment (CIRBE), launched in April of 2023, carries an advanced version of REPTile (REPTile-2), with 60 channels for electrons (0.25-6 MeV) and 60 channels for protons (6.5-100 MeV). With its high energy and time resolution, REPTile-2 has captured striking details of radiation belt electron dynamics [Li et al., GRL, 2024], further demonstrating that CubeSat missions can produce high-quality data and provide impact results on space weather study.
Li, X., Selesnick, R., Mei, Y., O’Brien, D., Hogan, B., Xiang, Z., et al. (2024). First results from REPTile‐2 measurements onboard CIRBE. Geophysical Research Letters, 51, e2023GL107521. https://doi. org/10.1029/2023GL107521

Author(s): Melanie Heil

European Space Agency

Abstract: Monitoring of the Earth’s and Sun’s environment is an essential task for the now- and forecasting of Space Weather and the modeling of interactions between the Sun and the Earth. For this reason, ESA is implementing the Distributed Space Weather Sensor System to observe the effects of solar activity from various orbits in Earth’s vicinity.
In particular, radiation belt monitoring data from a wide variety of locations in the magnetosphere is persistently requested by space weather modelers and service providers. In order to cover the Earth’s radiation belts a wide variation in altitude at low inclination, or more precisely in magnetic field characteristics, is needed. Therefore a mission in a geostationary-transfer orbit would be ideal to obtain the requested measurements, namely the particle fluxes of highly energetic electrons and protons together with the vector measurements of the magnetic field and the plasma characteristics.
The Space Weather Orbital Radiation Detector (SWORD) mission was first studied in ESA’s Concurrent Design Facility and currently industrial pre-Phase A studies are ongoing. The baseline mission scenario foresees two satellites in a GTO-like orbit slowly rotating to capture the full pitch angle distribution of energetic particles in the inner and outer radiation belt. The mission drivers are measurement optimisation as well as the data availability, continuity and timeliness.
The presentation will introduce the mission concept, current design and roadmap.

SWR3.3 Thu 7/11 17:30-18:30, room C2A – Mondego

Author(s): Nadja Reisinger, Fabio Bacchini, Giovanni Lapenta

KU Leuven; KU Leuven; KU Leuven

Abstract: We present a fully kinetic simulation of turbulent plasma at the Earth’s magnetotail, encompassing both ions and electrons. For this purpose, we used the particle in cell (PIC) method ECsim and introduced a time averaged Lagrangian frame. The simulation setup employs a global magnetohydrodynamic (MHD) simulation that provides the large-scale structure of Earth’s magnetosphere. The onset of magnetic reconnection in the magnetotail is used to initialize a local PIC simulation at the reconnecting tail region to resolve the kinetic processes that the MHD model does not include. We focus particularly on the turbulence generated in the magnetotail due to the earthward plasma flow induced by magnetic reconnection. This turbulence is crucial for the transport and mixing of plasma, as well as for the overall dynamics of the magnetotail. To delve deeper into these turbulent processes, we use the magnetotail simulation to initialize another simulation on smaller scales, allowing us to examine the evolved turbulence in greater detail. Using different simulations as starting points for subsequent ones, we show the interplay between large-scale magnetic structures and small-scale kinetic effects.

Author(s): Pouya Manshour, Constantinos Papadimitriou, Georgios Balasis, Milan Paluš

Department of Complex Systems, Institute of Computer Science of the Czech Academy of Sciences, Czech Republic; Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Greece; Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Greece; Department of Complex Systems, Institute of Computer Science of the Czech Academy of Sciences, Czech Republic

Abstract: Currently, there is no clear understanding of the comprehensive set of parameters that controls fluxes of relativistic electrons within the outer radiation belt. Herein, the methodology based on causal inference is applied for identification of factors that control fluxes of relativistic electrons in the outer belt. The patterns of interactions between the solar wind, geomagnetic activity and belt electrons have been investigated. We found a significant information transfer from solar wind, geomagnetic activity and fluxes of very low energy electrons (54 keV), into fluxes of relativistic (470 keV) and ultra-relativistic (2.23 MeV) electrons. We present evidence of a direct causal relationship from relativistic into ultra-relativistic electrons, which points to a local acceleration mechanism for electrons energization. It is demonstrated that the observed transfer of information from low energy electrons at 54 keV into energetic electrons at 470 keV is due to the presence of common external drivers such as substorm activity.

Author(s): Nigel P. Meredith, Thomas E. Cayton, Michael D, Cayton, Richard B. Horne

British Antarctic Survey, Cambridge, UK; Rio Rancho, NM, USA; Rio Rancho, NM, USA; British Antarctic Survey, Cambridge, UK

Abstract: Relativistic electrons cause internal charging on satellites and are a significant space weather hazard. In this study we analyse approximately 20 years of data from the US Global Positioning System (GPS) satellite NS41 to determine the conditions associated with the largest observed fluxes of relativistic electrons. At L = 4.5, the majority of the largest E = 2.0 MeV electron flux events were associated with either moderate (33 out of 50) or strong (11 out of 50) geomagnetic storms. Further out, at L = 6.5, weaker geomagnetic storms become more effective, with the majority of the largest events being associated with either moderate (30 out of 50) or weak (12 out of 50) geomagnetic storms. The 1 in 10 year flux levels were exceeded 3 times at L = 4.5 and 2 times at L = 6.5. These events were associated with moderate-to-strong CME-driven geomagnetic storms. Although the largest flux events were associated with moderate-to-strong CME driven storms, the majority of the fifty largest flux events at L = 4.5 (30 out of 50) and L = 6.5 (37 out of 50) were associated with high speed streams. Both solar drivers are thus very important for relativistic electron flux enhancements in GPS orbit. The 1 in 3 year flux level was not exceeded following any of the 15 largest geomagnetic storms as monitored by the Dst index, showing that the largest geomagnetc storms, most often associated with extreme space weather, do not lead to the most significant flux enhancements in GPS orbit.

Author(s): Stanislav Borisov, Sylvie Benck

UCLouvain/ELI-C/CSR; UCLouvain/ELI-C/CSR

Abstract: By now the Energetic Particle Telescope (EPT) on-board Proba-V (launched on 7th May 2013 onto a polar Low Earth Orbit of 820 km altitude) has provided quasi continuously flux spectra data for electrons (0.5–8 MeV), protons (9.5–248 MeV) and α-particles (38–980 MeV) with a time resolution of 2 seconds for more than a solar cycle. The data are transmitted to ground 3 – 4 times per day, where within several hours they are processed towards scientific data products available to the community.
This presentation will show observations of the above-mentioned particle fluxes during the mission, with particular focus on electron and proton flux evolution during extreme events like in March 2015, September 2017 and May 2024. The challenges and the techniques used for the most accurate flux extraction during such events will be discussed as well.

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): Christos Katsavrias, Sigiava Aminalragia-Giamini, Konstantina Thanasoula, Afroditi Nasi, Constantinos Papadimitriou, Ioannis A. Daglis

National and Kapodistrian University of Athens; SPARC; NKUA; National and Kapodistrian University of Athens; SPARC; National and Kapodistrian University of Athens

Abstract: Radial diffusion, driven by Ultra-Low Frequency (ULF) waves in the Pc4–5 band (2–25 mHz), has been established as one of the most important mechanisms that influence the dynamics of electrons in a quite broad energy range, as it can lead to both energization and loss of relativistic electrons in the outer Van Allen radiation belt. The dependence of ULF wave power spectral density and radial diffusion coefficients (DLL) on solar wind parameters has been investigated by some studies, but their relationship with the various solar and interplanetary drivers is far from well-studied and understood. In this study, we use the “SafeSpace” database, which contains radial diffusion coefficients and ULF wave power spectral density, and was created using THEMIS mission magnetic and electric field measurements during the 2011–2019 time-period. We conduct an extensive statistical analysis of DLL in order to investigate the relationships between the magnetic and electric components as well as their dependence on interplanetary drivers (i.e. High Speed Streams and Interplanetary Coronal Mass Ejections). Our results reveal an energy dependence of the radial diffusion coefficients as well as significant (periodic) variations of the DLL spectral profiles as a function of Roederer’s L*. Our findings highlight statistical, as well as physical, characteristics and aspects of DLL which are not included in most semi-empirical models typically used in radiation belt simulations. The absence of these aspects from the models introduces significant biases in the estimation of the outer belt relativistic electron environment. We further discuss the uncertainties of such efforts as well as the possible contribution of magnetosheath processes (e.g., jets and electron injections from the foreshock) and solar wind features (periodic density structures).

Author(s): Gwendoline MARC, Antoine BRUNET, Angélica SICARD, Quentin NENON

ONERA/DPHY, Université de Toulouse, Toulouse, France; ONERA/DPHY, Université de Toulouse, Toulouse, France; ONERA/DPHY, Université de Toulouse, Toulouse, France; CNRS – IRAP, Toulouse, France

Abstract: We have developed a new cyclo-synchrotron model to simulate the radio emission of Earth’s radiation belts as perceived by an instrument on the Moon. This model improves the previous version, which considered only relativistic electrons, offering increased accuracy and a more reliable estimate of observability. These enhancements provide deeper insights into the detectability and characteristics of radiation belt emissions.
Beyond forward modeling, we are addressing the inverse problem of reconstructing 3D electron distribution functions from 2D cyclo-synchrotron images. We are evaluating the feasibility of this inversion by testing various methods with images generated by our cyclo-synchrotron model.
The motivation for this work is to prepare for future missions that might deploy instruments on the Moon to capture 2D images of Earth’s radiation belts’ radio emissions. By developing inversion techniques, we aim to enable the retrieval of 3D information about the state of the radiation belts. This capability is crucial to extend our understanding of space weather phenomena and improving predictive models.
This work is co-financed by ESA and ONERA

Author(s): Oleksandr Koshkarov, Vania Jordanova, Misa Cowee, Kateryna Yakymenko

Los Alamos National Laboratory; Los Alamos National Laboratory; Los Alamos National Laboratory; Los Alamos National Laboratory

Abstract: During periods of increased magnetospheric convection, fresh plasma is carried into the inner magnetosphere, leading to the velocity distribution function of energetic electrons becoming anisotropic. The temperature anisotropy of tens of keV electrons generates whistler-mode chorus waves, which play a crucial role in the ring current and radiation belt dynamics through wave-particle interactions. Self-consistent simulations of the generation of plasma waves and their interactions with the energetic plasma populations is one of the biggest problems in the inner magnetosphere modeling. The conventional approach to simulate self-consistent plasma dynamics from first principles is the particle-in-cell (PIC) method. PIC codes are frequently utilized to simulate whistler waves in the magnetosphere. PIC is a simple and robust method, however it has a major limitation which is a statistical Monte-Carlo noise which can nontrivially affect weak plasma instabilities and wave-particle resonances making it challenging to apply to considered problem. In this work, we present extensive comparison of whistler wave simulations with VPIC code[1] against simulations with another first-principles code, the Spectral Plasma Solver (SPS [2]). SPS is a continuous Vlasov solver which is based on spectral expansion of the velocity space with Asymmetrically Weighted Hermite Polynomials (AWHP), together with discontinuous Galerkin (DG) approximation for coordinate space. The spectral AWHP expansion allows for a significant reduction in the number of degrees of freedom required to represent velocity space, while still retaining kinetic effects. The noiseless nature of SPS makes it particularly suitable to deal with weak instabilities considered in this work. To study generation of plasma waves, we take initial distribution of energetic electrons from large-scale inner magnetosphere simulations with RAM-SCB [3] ring current model. We investigate various aspects of simulations of weak whistler instabilities with the two codes and demonstrate that while PIC compares well with SPS and linear theory for larger anisotropies (strong instability), important discrepancies become apparent as the temperature anisotropy becomes smaller. Due to the high computational cost of weak whistler instabilities simulations with PIC codes, conversion studies are often unfeasible, and we argue that in these situations alternative approaches, like SPS, might be preferred. In the second part of the presentation we discuss how the simulations can be incorporated into the global inner magnetosphere modeling.[1] K.J. Bowers, B.J. Albright, L. Yin, W. Daughton, V. Roytershteyn, B. Bergen and T.J.T Kwan, Advances in petascale kinetic simulations with VPIC and Roadrunner, Journal of Physics: Conference Series 180, 012055, 2009.[2] O. Koshkarov, G. Manzini, G. L. Delzanno, C. Pagliantini, and Roytershteyn, V. The multi-dimensional Hermite-discontinuous Galerkin method for the Vlasov–Maxwell equations. Computer Physics Communications, 264:107866, 2021, doi: 10.1016/j.cpc.2021.107866.[3] Jordanova, V. K., Zaharia, S., and Welling, D. T. (2010), Comparative study of ring current development using empirical, dipolar, and self-consistent magnetic field simulations, J. Geophys. Res., 115, A00J11, doi:10.1029/2010JA015671.

Author(s): Balázs Heilig, János Lichtenberger, Veronika Barta, Dávid Koronczay, Lilla Murár-Juhász

HUN-REN Institute of Earth Physics and Space Science; Space Research Group, Eötvös Loránd University; Space Research Group, Eötvös Loránd University; HUN-REN Institute of Earth Physics and Space Science; Space Research Group, Eötvös Loránd University; Space Research Group, Eötvös Loránd University

Abstract: The May 10-11, 2024 superstorm was a remarkable event that had a significant impact on the Earth’s plasmasphere. As a consequence of the intense geomagnetic activity, the plasmasphere experienced severe erosion, resulting in a dramatic reduction in its size. The plasmapause, which is the boundary between the plasmasphere and the outer magnetosphere, moved inward, crossing the L = 2 magnetic shell.
Concurrently, in the remnant of the previously extended plasmasphere, the plasma mass density increased. This increase was followed by an unusual gradual daytime decrease on May 11th. The full recovery to the quiet state lasted for several days.
The dynamic evolution of the plasmapause was clearly observed by the LEO Swarm satellites. These satellites detected a fast equatorward movement of the mid-latitude ionospheric trough, occurring below 45° quasi-dipole magnetic latitude, in parallel with the contraction of the plasmasphere. As the plasmasphere was gradually refilled, the ionospheric trough gradually returned to higher latitudes, above 60°.
This event provided a unique opportunity to study the complex interactions between the solar wind, the Earth’s magnetosphere, and the ionosphere, as well as the resulting changes in the plasmasphere. The detailed observations from the Swarm satellites allowed for a comprehensive understanding of the storm’s impact on the near-Earth space environment and the associated plasma dynamics.

Author(s): Alina Grishina, Yuri Shprits, Alexander Drozdov, Dedong Wang, Bernhard Haas

GFZ Potsdam, University of Potsdam; GFZ Potsdam, University of Potsdam, UCLA; UCLA; GFZ Potsdam; GFZ Potsdam, University of Potsdam

Abstract: The Earth’s magnetic field is a complex entity with a heterogeneous structure, exhibiting varying strengths across different coordinates. Of particular interest is the South Atlantic Anomaly (SAA), a region characterized by a strong magnetic field and intense precipitation processes. Accurate modeling of this area demands a comprehensive approach, involving the calculation of magnetic fields and bounce times. Incorporating realistic field models, such as T89 for external and IGRF for internal fields, is essential for correct modeling. Furthermore, dividing the loss cone into drift and bounce components, correlated with geomagnetic latitudes, accounts for the disparate numbers of precipitated particles. By simulating a geomagnetic storm occurring in 2016 and validating our findings against observations from the ELFIN-L instrument on board the Lomonosov satellite in low-Earth orbit, we studied and compared precipitation activity during this event. Our investigation underscores the significance of incorporating the non-dipole loss cone model, leading to improved estimations of precipitated flux. Moreover, our study unveils a noteworthy connection between the magnetospheric waves activity and precipitation at low latitudes.

Author(s): Sarah A. Glauert, Richard B. Horne

British Antarctic Survey; British Antarctic Survey

Abstract: The electron flux in the Earth’s radiation belts can be highly variable, changing by orders of magnitude on a timescale of hours. Understanding this variability is important as high radiation levels can affect satellites orbiting through the belts, causing temporary issues or even permanent damage. One driver of this variability is the interaction between electromagnetic waves and electrons. Particularly during disturbed geomagnetic conditions, gyro-resonant interactions between chorus waves and electrons produce significant energy diffusion leading to the acceleration of lower energy (100s keV) electrons up to MeV energies.
We present results that use 2d diffusion simulations and comprehensive diffusion models to conduct a systematic investigation of where and when energy diffusion may have a significant effect on radiation belt dynamics. Our results demonstrate the effect that energy diffusion has on both pitch angle distributions and energy spectra, as well as the locations and conditions where cross diffusion plays a significant role.

Author(s): Konstantinos Papadakis, Maxime Grandin, Adnane Osmane, Minna Palmroth

University of Helsinki; University of Helsinki; University of Helsinki; University of Helsinki

Abstract: Electromagnetic ion cyclotron waves (EMIC) play a crucial role in the ensemble of processes that lead to electron loss in the magnetosphere. These waves typically occur within the low-frequency range of the electromagnetic spectrum. They are generated by the interaction of the Earth’s magnetic field with charged particles, particularly heavier ions, and they can influence the dynamics of the radiation belts, affect satellite operations, influence the ionospheric ionization levels and overall ionospheric dynamics. and contribute to the variability of the space weather around Earth. This study investigates the interaction of energetic electrons (100 keV – 5 MeV) with electromagnetic ion cyclotron (EMIC) wave packets using a three-dimensional (3D) massively-parallel particle tracer. The EMIC wave packets are allowed to propagate along the magnetic field lines up to a certain latitudinal limit where their magnitude diminishes. We employ the AE-9 model to initialize a realistic population of energetic electrons within the model at the equatorial plane. The pitch angle distribution of these electrons is based on in-situ measurements from space missions . We then integrate the motion of the electrons within the evolving EMIC wave field using a relativistic Boris pusher and monitor how their equatorial pitch angle changes as a result of the wave-particle interactions.

Author(s): Athanasia Charda, Christos Katsavrias, Ioannis A. Daglis

National and Kapodistrian University of Athens; National and Kapodistrian University of Athens; National and Kapodistrian University of Athens

Abstract: Electrons of the Earth’s outer radiation belt are highly dynamic and display significant variability, with fluxes changing by orders of magnitude. There have been several studies on the relationship between the flux and interplanetary parameters. In this study, we analyze the electron flux data collected during the Van Allen Probes mission, focusing specifically on the relativistic and ultra-relativistic electrons measured by the MagEIS and REPT instruments. Our analysis covers the evolution of electron fluxes for energies from 0.5 MeV up to ~10 MeV and their dependency on solar, solar wind and magnetospheric parameters. For each energy channel of the instruments, we examine the variables’ impact on the electron fluxes within the outer radiation belt, to identify which have high correlation. Additionally, we investigate the time dependence between each of the parameters and the electron flux variability, comparing the correlation of flux with an applied time lag on the parameters. We aim to identify the most significant parameters and the time lags with a better correlation for the average electron flux. We discuss the resulting findings in detail.

Author(s): Victor Montagud-Camps, Sergio Toledo-Redondo, Jerry Goldstein, Stephen A. Fuselier, Mats André, Inmaculada F. Albert, Aida Castilla, Alfonso Salinas, Jorge A. Portí, Enrique A. Navarro

Deparment of Electromagnetism and Electronics, University of Murcia, Murcia, 30100, SPAIN; Deparment of Electromagnetism and Electronics, University of Murcia, Murcia, 30100, SPAIN; Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA; Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA; Swedish Institute of Space Physics, Uppsala, Sweden; Deparment of Electromagnetism and Electronics, University of Murcia, Murcia, 30100, SPAIN; Deparment of Electromagnetism and Electronics, University of Murcia, Murcia, 30100, SPAIN; Deparment of Electromagnetism and Matter Physics, University of Granada, Granada, 18071, SPAIN; Deparment of Applied Physics, University of Granada, Granada, 18071, SPAIN; IRTIC Institute, University of Valencia, Paterna, 46980, SPAIN

Abstract: The main driver of magnetic reconnection at Earth’s magnetopause is the solar wind. Nonetheless,
the role played by heavy and cold ions in the outer magnetosphere cannot be neglected. Theoretical models and numerical simulations suggest that the presence of these particle species in the vicinity of the magnetopause renders magnetic reconnection less efficient due to a mechanism known as “mass-loading”. Thus, mapping the occurrence of cold and heavy ions in the magnetosphere will allow to improve the modelization of the solar wind and magnetosphere’s coupling and space weather predictions.
We have analized more than 8 years of data gathered by the Magnetospheric MultiScale (MMS) mission to characterize the properties and the prevalence of one magnetospheric plasma population, the so-called Warm Plasma Cloak (WPC). This plasma population, located between the magnetopause and the plasmasphere, has an ion temperature that ranges between the tens of eV to a few keV and is mainly composed of electrons, protons, and O+, with the latter signaling the ionospheric origin of this population. We will present the results of our statistical study, which has focused on the day-side magnetosphere and shows that the WPC is present about 50% of the time. Approximately 6% of the data intervals correspond to WPC with a substantial amount of O+, i.e., 𝜌𝑂+>2𝜌𝐻+. Using the Kp and Dst indices, we have related the presence of oxygen-rich WPC to the increase of geomagnetic activity in the 12 hours prior to their detection, in accordance with theoretical and numerical models of the generation of this population. Despite the relatively low occurrence rate of oxygen-rich WPC, this plasma population can play a significant role in the dynamics of magnetic reconnection at the magnetopause during the recovery phase of geomagnetic storms.

Author(s): Fadil Inceoglu, Paul T. M. Loto’aniu, Aspen Davis

University of Colorado Boulder / NOAA; University of Colorado Boulder / NOAA; University of Colorado Boulder / NOAA

Abstract: Ultra Low Frequency (ULF) waves are among the most studied plasma waves in Earth’s magnetosphere as they are important for space weather research because they are thought to play an important role in the dynamics of radiation belt electrons. Using the magnetic field measurements for the past 30 years from numerous GOES missions, from GOES-8 to GOES-17, we identified close to 30,000 events in each magnetic field component in MFA coordinate frame in the Pc5 range, which spans from 1.7 mHz to 7 mHz. To achieve this objective, we used a novel method, so-called the CLEAN algorithm. Using this database of ULF waves for the past 30 years, we then investigate the relationships between the ULF wave amplitudes and their frequencies in different locations and different solar wind conditions.
We plan to create a database where researchers can access to the ULF wave frequencies, amplitudes, and phases for a given date range. This database can be used in both radiation belt research and to better understand the physics of ULF waves. We will also include a discussion on our plan to incorporate the database in radiation belts models.

Author(s): Ingmar Sandberg, Timo Stein, Constantinos Papadimitriou, Sebastian Benoit, Giovanni Santin, Matteo Sgammini, Eric Guyader, Kjell Arne Aarmo, Kjell-Ove Orderud Skare, Matias Krogh Boge

1. Space Applications and Research Consultancy, 2. Department of Aerospace Science and Technology, National and Kapodistrian University of Athens,; Universitetet I Oslo, fmr. IDEAS; Space Applications and Research Consultancy; IDEAS, Norway; ESA/ESTEC, The Netherlands; European Commission, Ispra, Lombardy, Italy; European Commission, Ispra, Lombardy, Italy; Norwegian Space Agency; Norwegian Space Agency; Space Norway

Abstract: The Norwegian Radiation Monitor is a compact, single-particle telescope-based radiation monitor designed as an easily adaptable space radiation monitor for satellite missions in GEO, LEO, and HEO. The first NORM unit provides invaluable measurements of the radiation environment along the three-apogee, (TAP) highly elliptical orbit (HEO) of the Arctic Satellite Broadband Mission (ASBM). As ASBM encounters different radiation environment domains, NORM measures energetic charged particle fluxes accounting for the inner proton belt, the core of the dynamic outer electron radiation belt and the intermittent solar energetic protons.
The ground processing system of ASBM/NORM measurements includes the near-real-time processing chain from the NORM raw measurements to a complete Level-0 dataset (count-rates with auxiliary data) and to Level-1 dataset (electron and proton fluxes). For the implementation of NORM counts-to-flux methods different approaches were tested, prior to the ASBM launch, utilizing the characteristics of NORM response functions and analysing the expected radiation environment.
A report on the derivation and on the content of the first version of Level 1 datasets is provided. The datasets include measurements of proton fluxes for proton energies within 10-90 MeV and measurements of electron fluxes for electron energies within 0.5-5 MeV. The resulting coarse flux spectra for electrons and protons along HEO-TAP orbit can be utilised for a series of Space Weather applications and for the long-term characterisation of the radiation environment given the 15 years mission lifetime.
Acknowledgments
The development of NORM has been funded by ESA/ESTEC and the Norwegian Space Agency. The European Commission, the Norwegian Space Agency and Space Norway together own the rights to the data.

Author(s): Stavros Dimitrakoudis, Georgios Balasis, Adamantia Zoe Boutsi, Ioannis Daglis, Constantinos Papadimitriou, Christos Katsavrias, Marina Georgiou, Janos Lichtenberger

National and Kapodistrian University of Athens, Greece; National Observatory of Athens, Greece; IAASARS, National Observatory of Athens, National and Kapodistrian University of Athens, Greece; National and Kapodistrian University of Athens, Hellenic Space Center, Greece; IAASARS, National Observatory of Athens, National and Kapodistrian University of Athens, Greece; National and Kapodistrian University of Athens, Greece; National and Kapodistrian University of Athens, IAASARS, National Observatory of Athens, Greece; Eötvös Loránd University, ELKH-ELTE Space Research Group, Hungary

Abstract: Radial diffusion, generated by ultra-low frequency (ULF) waves, is an important process for the transport of electrons in the outer radiation belt. Ground magnetometers give us constant observations of such ULF waves but their usefulness is limited by the models used to transform ground measurements into their progenitor fields in space. A typical assumption is that of a dipole field, and so measurements can only be reliably performed during the day. We have chosen a series of magnetometer stations at different sets of geomagnetic latitudes, with stations in each set separated by several hours in longitude, and calculated radial diffusion coefficients from 11 years of their data. By comparing the mismatch of their results when they were in different time sectors, and for different values of Kp, we obtained an empirical correction factor for measurements conducted before dawn or after dusk. This will be useful for projects requiring a longitudinally limited array of magnetometers or for parts of the world where such coverage is limited.

Author(s): Ian Mann, Chris Cully, Robert Fedosejevs, David K Milling, Greg Enno, Michael Lipsett, Robert E Zee, Robert Rankin, Martin G Connors, Kathryn A McWilliams, William E Ward, Robyn A Fiori, Leonid Olifer, Louis Ozeke, Robert A Marshall, David Cullen, David Barona, Andrew D Howarth, Andrew W Yau

University of Alberta, Department of Physics, Edmonton, AB, Canada.; University of Calgary, Calgary, AB, Canada; University of Alberta, Department of Electrical and Computer Engineering, Edmonton, AB, Canada; University of Alberta, Department of Physics, Edmonton, AB, Canada.; University of Alberta, Department of Physics, Edmonton, AB, Canada.; University of Alberta, Department of Mechanical Engineering, Edmonton, AB, Canada; University of Toronto, Toronto, ON, Canada; University of Alberta, Department of Physics, Edmonton, AB, Canada.; Athabasca University, Athabasca, AB, Canada.; University of Saskatchewan, Saskatoon, SK, Canada.; University of New Brunswick, Fredericton, NB, Canada.; Natural Resources Canada, Ottawa, ON, Canada.; University of Alberta, Department of Physics, Edmonton, AB, Canada.; University of Alberta, Department of Physics, Edmonton, AB, Canada.; University of Colorado at Boulder, Aerospace Engineering Sciences, Boulder, United States.; University of Alberta, Department of Physics, Edmonton, AB, Canada.; University of Alberta, Department of Physics, Edmonton, AB, Canada.; University of Calgary, Calgary, AB, Canada; University of Calgary, Calgary, AB, Canada

Abstract: The RADiation Impacts on Climate and Atmospheric Loss Satellite (RADICALS) is a low-Earth orbiting Canadian small satellite mission investigating the transport of space radiation into the atmosphere, and its impact on Earth’s climate. Scheduled for launch in late 2026, or early 2027, the mission will launch into a polar orbit with an integrated payload comprising two back-to-back look direction High Energy Particle (HEP)telescopes, two back-to-back X-Ray Imagers (XRI) to remote sense energetic particle precipitation using back-scattered Bremsstrahlung X-rays, and boom mounted FluxGate Magnetometer (FGM) and Search Coil Magnetometers (SCM). Using an innovative Thomson spin-stabilized configuration, the satellite will sample the pitch angle distributions in the spin-plane twice per spin. The back-to-back HEP look directions allow for a contemporaneous view of the down-going and back-scattered up-going electrons, at the same time as XRI remote-senses the related Bremsstrahlung, and the magnetometers provide in-situ magnetic signatures of a range of plasma waves. The key measurement of the pitch angle resolved energetic electron precipitation (EEP) and related back-scatter, including a resolved loss cone, will allow a detailed assessment of the energetic particle energy input to the atmosphere. Measurements of EEP, in addition to measurements of solar energetic particle (SEP) precipitation, will represent a critical data set for assessing the role of space radiation in the climate system, for example through the catalytic destruction of ozone in the middle atmosphere by NOx and HOx. Accurately quantifying the impacts of this space radiation on climate requires accurate and loss cone-resolved characterization of the flux of these precipitating energetic particles for inclusion into whole atmosphere models. The RADICALS explorer will also enable research into potentially catastrophic space-weather radiation effects on satellite infrastructure, and assess impacts on space weather-related interruptions to high frequency radio communications including in relation to aircraft operations in polar regions.

Author(s): Livia R. Alves, Ligia A. da Silva, Alexandre J. O. Silva, Joaquim E. R. Costa, Laysa C. A. Resende, Karen J. C. Ferreira, Gislayne M. Nóbrega

INPE; State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences.; National Institute for Space Research – INPE, São José dos Campos, SP, Brazil.; INPE; INPE; State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences.; National Institute for Space Research – INPE, São José dos Campos, SP, Brazil.; INPE; INPE

Abstract: Throughout geomagnetic storms, relativistic electrons trapped in the Earth’s magnetosphere can be accelerated, lost, or remain unchanged. Disturbances in the magnetospheric plasma cause several processes, including waves that interact with charged particles and lead to the variability of the outer radiation belt electron flux. Monitoring relativistic electron variability is important for the safety of satellite operations and near-Earth space missions in general. We used in-situ measurements from several space missions to model relativistic electron flux variability in the radiation belt. In this context, improving the estimate of diffusion coefficients is mandatory for modeling success. The diffusion coefficients indicate the effectiveness of a specific physical process in accelerating or losing electrons in the outer radiation belt. There are several results in the literature for space weather applications that show diffusion coefficients derived empirically as a function of Kp-index. In this work, we use a specific model to compare the estimates of diffusion coefficients based on the Kp-index by using a neural network-based Kp-index (NN-Kp) for extreme storms that occurred in the late 20 years. We also tested the proposed NN-Kp’s ability to compute nowcast diffusion coefficients and compared our results with those provided by the definitive Kp index. For the investigated storms, diffusion coefficients based on NN-Kp show good agreement with those calculated using the definitive Kp index. These findings have the potential to improve space weather applications for the nowcasting of relativistic electrons in the radiation belt under extreme storms.

Author(s): Jay Albert, Frantisek Nemec, Ondrej Santolik

AFRL; Charles University; Institute of Atmospheric Physics, CAS

Abstract: Radiation belt electrons within the plasmasphere are believed to be strongly affected by cyclotron-resonant interactions with waves from various sources. Such waves include plasmaspheric hiss, lightning-generated whistlers, and VLF waves from large Navy transmitters worldwide. Russian Alpha radio navigation transmissions around 12 kHz may also have to potential to contribute, though this depends on their radiated wave power, which has been poorly documented. Recently, have been comprehensively observed and characterized by the Van Allen Probes, as well as modeled from source to space using a full-wave calculation of trans-ionospheric propagation coupled to 3D ray-and-power tracing, allowing detailed comparisons of field amplitudes and wave normal angles. We find the nominal, frequently quoted radiated power for these transmitters to be a large overestimate, and survey other evidence supporting this. We also present quasi-linear pitch angle and energy diffusion coefficients for these waves. By comparing to previously considered wave sources, we show where the effects are expected to be significant, and also where they may be serve as useful diagnostics for other aspects of wave-particle interactions, such as the prevalence of wave ducting.

Author(s): G. M. Nóbrega, L. A. Da Silva, F. Egito, L. R. Alves, V. Deggeroni

National Institute for Space Research – INPE; National Institute for Space Research – INPE, State Key Laboratory for Space Weather; Federal University of Campina Grande; National Institute for Space Research – INPE; National Institute for Space Research – INPE

Abstract: The coupling between solar wind structures and the magnetosphere is a very complex phenomenon, which can trigger several physical processes in the Earth’s magnetosphere. Therefore, two case studies were selected, in which two different types of variability in the relativistic electron flux in the outer radiation belt were observed. These events occurred under the influence of Interplanetary Coronal Mass Ejections (ICMEs), which can present different characteristics and, thus, lead to different physical processes within the inner magnetosphere, which directly impact the variability of the relativistic electron flux trapped in this region. To understand the main characteristics of these ICMEs, as well as the physical processes in the outer belt, and their respective impacts on the variability of the flux of trapped electrons, data from instruments on board the ACE satellite at the Lagrangian point L1 and the twin Van Allen probes in situ (near-equatorial, elliptical orbit) in the radiation belts are used. The first selected event occurred between December 21 and 22, 2014 and was characterized by a decrease in particle fluxes known as “dropout”. The second event occurred between June 22 and 23, 2015 and consisted of a dropout followed by “enhancement” of the electron flow, that is, a considerable increase that occurred a few hours after the decrease. For the first case, it was found that ultra-low frequency (ULF) wave activity resulted in loss processes to the magnetopause through outward radial diffusion. The incidence of high-band whistler mode Chorus waves influenced an attempt to repopulate the fluxes, that was not achieved due to the combined action of low-band Chorus and ULF waves. For the second event, significant compression of the magnetopause was recorded, reaching five Earth radii at the time of structure impact, combined with intense ULF activity throughout the entire dropout period. This resulted in an outward radial diffusion movement, and subsequent loss to the magnetopause. The enhancement was concomitant with a decrease in the intensity of ULF waves and there was no significant Chorus activity during this event, indicating that other physical mechanisms must be investigated.

Author(s): Evangelia Christodoulou, Christos Katsavrias, Ioannis A. Daglis

Department of Physics, National and Kapodistrian University of Athens; Department of Physics, National and Kapodistrian University of Athens; (1) Department of Physics, National and Kapodistrian University of Athens, (2) Hellenic Space Center, Athens, Greece

Abstract: The behavior of sub-relativistic electrons in the Earth’s outer radiation belt and ring current is crucial for understanding space weather dynamics and improving space weather prediction models. This study utilizes electron flux data from the Hope and MagEIS instruments on board the RBSP satellites (1-400 keV), along with solar parameters and geomagnetic indices obtained from the OmniWeb2 data service. We calculate the correlation coefficients between these parameters and electron flux, including time lags to highlight any temporal dependencies. Our analysis shows significant correlations between source electron (10-100 keV) population and substorm activity, while also showing that seed electrons (100-400 keV) are not purely driven by substorm events. By introducing time lags, we observed a delayed response of electron flux to changes in solar wind conditions, and we identified specific time lag periods where the correlation peaks. This work provides important information and forms the basis for future research.

Author(s): Bourdarie Sebastien, Caron Pablo, Kučera Rian, Vatterodt Corinna, Ecoffet Robert

ONERA; ONERA; Solenix; Solenix; CNES

Abstract: ICARE-NG² is the third generation of the CNES-ONERA-EREMS radiation monitor. It benefits from more than 20 years of heritage. The very first unit, ICARE, flown on SAC-C at LEO and was launched in December 2000. Then a new generation was developed, reduced in size, ICARE-NG and flew on Jason-2 (LEO), SAC-D (LEO), Jason-3 (LEO) and E7C (EOR+GEO). The first ICARE-NG² unit was then implemented on Hotbird-13F (EOR+GEO) followed by a second one on HotBird-13G (EOR+GEO) and was respectively launched on 15-Oct-2022 and 03-Nov-2022.
Within “S2P S1-SW-10.01 SPACE WEATHER DATA SYSTEM ENHANCEMENT: ICARE-NG PDC” ONERA and Solenix were in charge of implementing the ICARE-NG² Payload Data Center.
L1 data will be presented, their real time processing as well as their availability on ESA space weather portal.

Author(s): Yalei SHI, Vincent LESUR, Erwan THÉBAULT

IPGP, UMR7154; IPGP, UMR7154; LMV, UMR 6524

Abstract: The geomagnetic field, as observed at the Earth’s surface or satellite altitudes, is the combination of signals generated by several sources: internal sources due to the liquid outer core flow, magnetized rocks in the lithosphere and induced electric currents in the crust and mantle, and external sources due to electric currents in the ionosphere and magnetosphere. We describe an approach for modeling the magnetospheric contribution from the geomagnetic field, based on magnetic observatory data. Magnetic survey satellite data provide a good spatial resolution for fields generated in the Earth, but their spatio-temporal resolution is limited for rapidly varying external magnetic fields. In contrast, geomagnetic observatories are distributed over a large range of latitudes and longitudes and record minute-averaged (or second-averaged) vector magnetic data. As a result, geomagnetic observatories provide datasets with high temporal resolution that are particularly well suited to characterize magnetospheric signals. The aim of this work is to reliably characterize the magnetospheric contributions observed at geomagnetically quiet time (Dst between -30 nT and 30 nT) up to spherical harmonic degree 6, with a temporal resolution of one hour, for the period from 1999 to 2024. The adopted approach is based on the Kalman filter and correlation-based modeling. We derive a time series of model distributions that exhibit behaviors analogous to those observed in the magnetospheric ring current index (RC), as determined by other methodologies: correlation coefficient between our modelling q10 and RC index is 0.9. Semi-annual, monthly and daily variations as well as tidal variations are observed in the temporal spectrum domain of all magnetospheric modeled Gauss coefficients. A key element of our approach is ensuring that all model parameters are accompanied by robust error estimates. We plan to use our hourly magnetospheric models to produce candidate models for the 14th edition of the International Geomagnetic Reference Field.

Author(s): Olga Kryakunova, Botakoz Seifullina, Anatoliy Belov, Artem Abunin, Maria Abunina, Irina Tsepakina, Nikolay Nikolayevskiy, Nataly Shlyk

Institute of Ionosphere; Institute of Ionosphere; Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation; Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation; Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation; Institute of Ionosphere; Institute of Ionosphere; Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation

Abstract: The behavior of high-energy electrons in the Earth’s magnetosphere is one of the most actual problems in the physics of magnetosphere and space weather. Enhancements of high-energy magnetospheric electrons with energies >2 MeV in geostationary orbit are associated with disturbances arriving at the Earth from interplanetary space. Interplanetary disturbances can be caused by high-speed solar wind streams arriving at the Earth from coronal holes, coronal mass ejections from solar flares and filament disappearances, as well as disturbances from mixed solar sources. Solar sources of disturbances were determined for all events of electron enhancements in which the daily fluence of magnetospheric electrons exceeded dangerous level in 1995-2023. The distribution of electron enhancement events was constructed depending on solar sources. It was shown that the overwhelming majority of electron enhancements were associated with high-speed streams from coronal holes. Examples of such events, characteristic of different classes of solar sources, are considered.

Author(s): Georgios Balasis, Stavros Dimitrakoudis, Adamantia Zoe Boutsi, Ioannis A. Daglis, Constantinos Papadimitriou, Marina Georgiou, Christos Katsavrias, János Lichtenberger

National and Kapodistrian University of Athens; National and Kapodistrian University of Athens; National and Kapodistrian University of Athens; National and Kapodistrian University of Athens; National and Kapodistrian University of Athens; National and Kapodistrian University of Athens; National and Kapodistrian University of Athens; Eötvös University

Abstract: The FARBES (Forecast of Actionable Radiation Belt Scenarios) project aims to bring together various ground-based real-time inputs in order to nowcast the radiation belt environment with a physics-based model, in a quick and affordable way. One of the main inputs is radial diffusion coefficients, which govern the interaction of ULF waves with particles in the radiation belts. Since the goal is consistency in coverage and data attainability, the diffusion coefficients will be calculated indirectly from ground magnetometer measurements, from the EMMA (European Meridional Magnetometer Array) and ENIGMA (HellENIc GeoMagnetic Array) arrays in Europe. Geomagnetic field measurements in the Pc5 frequency range are converted to power spectral density, which is then mapped out to the equatorial plane in space using an algorithm. From that we can calculate diffusion coefficients which can then be used in an upgraded version of the Salammbô radiation belt modeling code to provide predictions for satellite operators. Here we present an overview of the methods, strengths and limitations of this approach, which is a work in progress.

Author(s): Soboh ALQEEQ, D. Fontaine, O. Le Contel, M. Akhavan Tafti, E. Cazzola, Tsige Atilaw

Laboratoire de Physique des Plasmas (LPP), UMR7648, CNRS, Sorbonne Université, Université Paris-Saclay, Observatoire de Paris, Ecole Polytechnique Institut Polytechnique de Paris, Paris, France; Laboratoire de Physique des Plasmas (LPP), UMR7648, CNRS, Sorbonne Université, Université Paris-Saclay, Observatoire de Paris, Ecole Polytechnique Institut Polytechnique de Paris, Paris, France; Laboratoire de Physique des Plasmas (LPP), UMR7648, CNRS, Sorbonne Université, Université Paris-Saclay, Observatoire de Paris, Ecole Polytechnique Institut Polytechnique de Paris, Paris, France; Climate and Space Sciences and Engineering (CLaSP), University of Michigan, Ann Arbor, MI, Climate and Space Sciences and Engineering (CLaSP), University of Michigan, Ann Arbor, MI, USA; Laboratoire de Physique des Plasmas (LPP), UMR7648, CNRS, Sorbonne Université, Université Paris-Saclay, Observatoire de Paris, Ecole Polytechnique Institut Polytechnique de Paris, Paris, France; Climate and Space Sciences and Engineering (CLaSP), University of Michigan, Ann Arbor, MI, Climate and Space Sciences and Engineering (CLaSP), University of Michigan, Ann Arbor, MI, USA

Abstract: In the present study, we present a comparative analysis of the Earth’s magnetospheric dynamics in response to the intense geomagnetic storm of 19th December 2015, marked by a substantial decrease in the SYM-H index to -188 nT, with particular focus on the variations in magnetic flux content (MFC). During this event, we had the chance to have observations on the day side and on the nightside and at different distances in the magnetosphere (OMNI, Van Allen Probes, GOES, THEMIS, MMS, Cluster). Using these various observations together with the Tsyganenko T96 model, we estimated the MFC in the inner magnetosphere. It is found that in comparison to pre-storm conditions, MCF decreased during SSC by 17% and in the main phase by 27% but it gradually rebounded (swelled) during 3 following days of the recovery phase reducing the decrease to 22%, 14% and 8% respectively. The importance of storm-time magnetospheric dynamics in the field of space weather forecasting is emphasized by these findings and calls for further studies.