The March 2015 Superstorm Revisited: Phase Space Density Profiles and Fast ULF Wave Diffusive Transport

TitleThe March 2015 Superstorm Revisited: Phase Space Density Profiles and Fast ULF Wave Diffusive Transport
Publication TypeJournal Article
Year of Publication2019
AuthorsOzeke, LG, Mann, IR, Claudepierre, SG, Henderson, M, Morley, SK, Murphy, KR, Olifer, L, Spence, HE, Baker, DN
JournalJournal of Geophysical Research: Space Physics
Date Published01/2019
KeywordsLocal Acceleration; March 2015 storm; Phase space density; radial diffusion; Radiation belt; ULF waves; Van Allen Probes
AbstractWe present the temporal evolution of electron Phase Space Density (PSD) in the outer radiation belt during the intense March 2015 geomagnetic storm. Comparing observed PSD profiles as a function of L* at fixed first, M, and second, K, adiabatic invariants with those produced by simulations is critical for determining the physical processes responsible for the outer radiation belt dynamics. Here we show that the bulk of the accelerated and enhanced outer radiation belt population consists of electrons with K < 0.17 G1/2Re. For these electrons, the observed PSD versus L* profiles during the recovery phase of the storm have a positive radial gradient. We compare the observed temporal evolution of the PSD profiles during the recovery phase with those produced by radial diffusion simulations driven by observed Ultralow Frequency wave power as measured on the ground. Our results indicate that the dominant flux enhancement, inside L* < 5, in the heart of the outer radiation belt during the March 2015 geomagnetic storm is consistent with that produced by fast inward radial diffusion of electrons from a dynamic outer boundary driven by enhanced Ultralow Frequency wave power.
URLhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026326
DOI10.1029/2018JA026326
Short TitleJ. Geophys. Res. Space Physics


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