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Evidence of Sub‐MeV EMIC‐Driven Trapped Electron Flux Dropouts From GPS Observations
Author(s) -
Hendry A. T.,
Rodger C. J.,
Clilverd M. A.,
Morley S. K.
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2021gl092664
Subject(s) - van allen radiation belt , emic and etic , electron , physics , van allen probes , atomic physics , ion , flux (metallurgy) , scattering , cyclotron , electron scattering , nuclear physics , magnetosphere , plasma , materials science , optics , metallurgy , quantum mechanics , sociology , anthropology
For many years, it was believed that resonant interactions between electromagnetic ion cyclotron (EMIC) waves and radiation belt electrons were restricted to electron energies >1–2 MeV. In recent years, however, a growing body of experimental evidence has shown that EMIC waves can cause the scattering loss of electrons down to sub‐MeV energies. Using measurements of trapped electron flux from the Global Positioning System satellite constellation, we investigate the ability of EMIC waves to cause significant depletions of radiation belt electron populations between 4 ≤ L * ≤ 5. For the first time, we present statistical evidence demonstrating global decreases in sub‐MeV trapped electron flux in response to EMIC wave activity. Although we find that electron losses extend down to sub‐MeV energies, we also show strong statistical support for the ability of EMIC waves to preferentially cause substantial depletions of ultra‐relativistic electrons in the radiation belts.