The Acceleration of Ultrarelativistic Electrons During a Small to Moderate Storm of 21 April 2017

TitleThe Acceleration of Ultrarelativistic Electrons During a Small to Moderate Storm of 21 April 2017
Publication TypeJournal Article
Year of Publication2018
AuthorsZhao, H, Baker, DN, Li, X, Jaynes, AN, Kanekal, SG
JournalGeophysical Research Letters
Date Published06/2018
KeywordsEnergy‐dependent acceleration; Geomagnetic storms; Inward radial diffusion; Local Acceleration; Radiation belts; Ultra‐relativistic electrons; Van Allen Probes
AbstractThe ultrarelativistic electrons (E > ~3 MeV) in the outer radiation belt received limited attention in the past due to sparse measurements. Nowadays, the Van Allen Probes measurements of ultrarelativistic electrons with high energy resolution provide an unprecedented opportunity to study the dynamics of this population. In this study, using data from the Van Allen Probes, we report significant flux enhancements of ultrarelativistic electrons with energies up to 7.7 MeV during a small to moderate geomagnetic storm. The underlying physical mechanisms are investigated by analyzing and simulating the evolution of electron phase space density. The results suggest that during this storm, the acceleration mechanism for ultrarelativistic electrons in the outer belt is energy‐dependent: local acceleration plays the most important role in the flux enhancements of ~3–5 MeV electrons, while inward radial diffusion is the main acceleration mechanism for ~7 MeV electrons at the center of the outer radiation belt.
URLhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078582
DOI10.1029/2018GL078582
Short TitleGeophys. Res. Lett.


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