Publication Date:
2014-02-14
Description:
[1] We study the effect of electromagnetic ion cyclotron (EMIC) waves on the loss and pitch-angle scattering of relativistic and ultra-relativistic electrons during the recovery phase of a moderate geomagnetic storm on October 11, 2012. The EMIC wave activity was observed in-situ on the Van Allen Probes and conjugately on the ground across the CARISMA array throughout an extended 18-hour interval. However, neither enhanced precipitation of 〉0.7 MeV electrons, nor reductions in Van Allen Probe 90 o pitch-angle ultra-relativistic electron flux were observed. Computed radiation belt electron pitch-angle diffusion rates demonstrate that rapid pitch-angle diffusion is confined to low pitch angles and cannot reach 90 o . For the first time, from both observational and modeling perspectives, we show evidence of EMIC waves triggering ultra-relativistic (~2-8 MeV) electron loss, but which is confined to pitch angles below around 45 degrees and not affecting the core distribution.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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