EPP

地球与行星物理

ISSN  2096-3955

CN  10-1502/P

Exohiss wave enhancement following substorm electron injection in the dayside magnetosphere
ZhongLei Gao, ZhenPeng Su, FuLiang Xiao, HuiNan Zheng, YuMing Wang, Shui Wang, H. E. Spence, G. D. Reeves, D. N. Baker, J. B. Blake, H. O. Funsten
doi: 10.26464/epp2018033
Exohiss is a low-frequency structureless whistler-mode emission potentially contributing to the precipitation loss of radiation belt electrons outside the plasmasphere. Exohiss is usually considered the plasmaspheric hiss leaked out of the dayside plasmapause. However, the evolution of exohiss after the leakage has not been fully understood. Here we report the prompt enhancements of exohiss waves following substorm injections observed by Van Allen Probes. Within several minutes, the energetic electron fluxes around 100 keV were enhanced by up to 5 times, accompanied by an up to 10-time increase of the exohiss wave power. These substorm-injected electrons are shown to produce a new peak of linear growth rate in the exohiss band (< 0.1fce). The corresponding path-integrated growth rate of wave power within 10° latitude of the magnetic equatorial plane can reach 13.4, approximately explaining the observed enhancement of exohiss waves. These observations and simulations suggest that the substorm-injected energetic electrons could amplify the preexisting exohiss waves.
Keywords: exohiss, substorm injection, radiation belt, whistler-mode instability

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