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Transport and Loss of Ring Current Electrons Inside Geosynchronous Orbit During the 17 March 2013 Storm

Aseev N. A., Y. Y. Shprits, D. Wang, J. Wygant, A. Y. Drozdov, A. C. Kellerman, G. D. Reeves, (2019), Transport and Loss of Ring Current Electrons Inside Geosynchronous Orbit During the 17 March 2013 Storm, J. of Geophys. Res. [Space Physics], 124, 915-933, doi:10.1029/2018JA026031

Abstract

Abstract Ring current electrons (1–100 keV) have received significant attention in recent decades, but many questions regarding their major transport and loss mechanisms remain open. In this study, we use the four-dimensional Versatile Electron Radiation Belt code to model the enhancement of phase space density that occurred during the 17 March 2013 storm. Our model includes global convection, radial diffusion, and scattering into the Earth's atmosphere driven by whistler-mode hiss and chorus waves. We study the sensitivity of the model to the boundary conditions, global electric field, the electric field associated with subauroral polarization streams, electron loss rates, and radial diffusion coefficients. The results of the code are almost insensitive to the model parameters above 4.5 RERE, which indicates that the general dynamics of the electrons between 4.5 RE and the geostationary orbit can be explained by global convection. We found that the major discrepancies between the model and data can stem from the inaccurate electric field model and uncertainties in lifetimes. We show that additional mechanisms that are responsible for radial transport are required to explain the dynamics of ≥40-keV electrons, and the inclusion of the radial diffusion rates that are typically assumed in radiation belt studies leads to a better agreement with the data. The overall effect of subauroral polarization streams on the electron phase space density profiles seems to be smaller than the uncertainties in other input parameters. This study is an initial step toward understanding the dynamics of these particles inside the geostationary orbit.

Authors (sorted by name)

Aseev Drozdov Kellerman Reeves Shprits Wang Wygant

Journal / Conference

Journal Of Geophysical Research (Space Physics)

Acknowledgments

The authors acknowledge use of NASA/GSFC's Space Physics Data Facility's OMNIWeb service, and OMNI data. The Kp index was provided by GFZ Potsdam. The authors are grateful to the RBSP‐ECT team for the provision of Van Allen Probes observations. All RBSP‐ECT data are publicly available at the web site http://www.RBSP-ect.lanl.gov/. This research was supported by the Helmholtz‐Gemeinschaft (HGF; http://10.13039/501100001656), NASA grants NNX15AI94G and NNX16AG78G, NSF grant AGS‐1552321, and project PROGRESS funded by EC | Horizon 2020 Framework Programme (H2020; http://10.13039/100010661; 637302). The research has been partially funded by Deutsche Forschungsgemeinschaft (DFG) through grant CRC 1294 Data Assimilation, Project B06. Processing and analysis of the ECT data was supported by Energetic Particle, Composition, and Thermal Plasma (RBSP‐ECT) investigation funded under NASA's Prime contract NAS5‐01072. The work by the EFW team was conducted under JHU/APL contract 922613 (RBSP‐EFW). This work used computational and storage services associated with the Hoffman2 Shared Cluster provided by UCLA Institute for Digital Research and Education's Research Technology Group. The authors thank the developers of the IRBEM library, which was adapted for use in the current study and Daniel Weimer for the provision of the codes for global electric field model. The authors are grateful to Sharon Uy for the help with editing the paper. The authors thank Irina Zhelavskaya and Frederic Effenberger for useful discussions. The authors thank anonymous reviewers for the insightful comments.

Grants

637302 AGS‐1552321 NNX15AI94G NNX16AG78G PROGRESS

Bibtex

@article{doi:10.1029/2018JA026031,
author = {Aseev, N. A. and Shprits, Y. Y. and Wang, D. and Wygant, J. and Drozdov, A. Y. and Kellerman, A. C. and Reeves, G. D.},
title = {Transport and Loss of Ring Current Electrons Inside Geosynchronous Orbit During the 17 March 2013 Storm},
journal = {Journal of Geophysical Research: Space Physics},
volume = {124},
number = {2},
pages = {915-933},
keywords = {ring current electrons, magnetospheric convection, ensemble modeling, inner magnetosphere, electron transport, wave-particle interactions},
doi = {10.1029/2018JA026031},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JA026031},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JA026031},
abstract = {Abstract Ring current electrons (1–100 keV) have received significant attention in recent decades, but many questions regarding their major transport and loss mechanisms remain open. In this study, we use the four-dimensional Versatile Electron Radiation Belt code to model the enhancement of phase space density that occurred during the 17 March 2013 storm. Our model includes global convection, radial diffusion, and scattering into the Earth's atmosphere driven by whistler-mode hiss and chorus waves. We study the sensitivity of the model to the boundary conditions, global electric field, the electric field associated with subauroral polarization streams, electron loss rates, and radial diffusion coefficients. The results of the code are almost insensitive to the model parameters above 4.5 RERE, which indicates that the general dynamics of the electrons between 4.5 RE and the geostationary orbit can be explained by global convection. We found that the major discrepancies between the model and data can stem from the inaccurate electric field model and uncertainties in lifetimes. We show that additional mechanisms that are responsible for radial transport are required to explain the dynamics of ≥40-keV electrons, and the inclusion of the radial diffusion rates that are typically assumed in radiation belt studies leads to a better agreement with the data. The overall effect of subauroral polarization streams on the electron phase space density profiles seems to be smaller than the uncertainties in other input parameters. This study is an initial step toward understanding the dynamics of these particles inside the geostationary orbit.},
year = {2019}
}