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Characteristics of High‐Energy Proton Responses to Geomagnetic Activities in the Inner Radiation Belt Observed by the RBSP Satellite
Author(s) -
Xu Jiyao,
He Zhaohai,
Baker D. N.,
Roth Ilan,
Wang Chi,
Kanekal S. G.,
Jaynes A. N.,
Liu Xiao
Publication year - 2019
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2018ja026205
Subject(s) - van allen radiation belt , van allen probes , geomagnetic storm , proton , earth's magnetic field , equator , physics , satellite , south atlantic anomaly , geology , storm , geophysics , atmospheric sciences , magnetosphere , meteorology , astronomy , nuclear physics , magnetic field , latitude , plasma , quantum mechanics
High‐energy trapped particles in the radiation belts constitute potential threats to the functionality of satellites as they enter into those regions. In the inner radiation belt, the characteristics of high‐energy (>20 MeV) protons variations during geomagnetic activity times have been studied by implementing 4‐year (2013–2016) observations of the Van Allen probes. An empirical formula has been used to remove the satellite orbit effect, by which proton fluxes have been normalized to the geomagnetic equator. Case studies show that the region of L < 1.7 is relatively stable, while L > 1.7 is more dynamic and the most significant variation of proton fluxes occurs at L = 2.0. The 4‐year survey at L = 2.0 indicates that for every geomagnetic storm, sharp descent in proton fluxes is accompanied by the corresponding depression of SYM‐H index, with a one‐to‐one correspondence, regardless of the storm intensity. Proton flux dropouts are synchronous with SYM‐H reduction with similar short timescales. Our observational results reveal that high‐energy protons in the inner radiation belt are very dynamic, especially for the outer zone of the inner belt, which is beyond our previous knowledge.