Energetic proton spectra measured by the Van Allen Probes

TitleEnergetic proton spectra measured by the Van Allen Probes
Publication TypeJournal Article
Year of Publication2017
AuthorsSummers, D, Shi, R, Engebretson, MJ, Oksavik, K, Manweiler, JW, Mitchell, DG
JournalJournal of Geophysical Research: Space Physics
Date Published09/2017
KeywordsEMIC-wave -proton scattering; proton ring current; Van Allen Probes
AbstractWe test the hypothesis that pitch-angle scattering by electromagnetic ion cyclotron (EMIC) waves can limit ring current proton fluxes. For two chosen magnetic storms, during March 17-20, 2013 and March 17-20, 2015, we measure proton energy spectra in the region 3 ≤ L ≤ 6 using the RBSPICE B instrument on the Van Allen Probes. The most intense proton spectra are observed to occur during the recovery periods of the respective storms. Using proton precipitation data from the POES (NOAA and MetOp) spacecraft, we deduce that EMIC wave action was prevalent at the times and L-shell locations of the most intense proton spectra. We calculate limiting ring current proton energy spectra from recently developed theory. Comparisons between the observed proton energy spectra and the theoretical limiting spectra show reasonable agreement. We conclude that the measurements of the most intense proton spectra are consistent with self-limiting by EMIC wave scattering.
Short TitleJ. Geophys. Res. Space Physics

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