Journal article
Simulation of energy‐dependent electron diffusion processes in the Earth's outer radiation belt
Journal of geophysical research. Space physics, Vol.121(5), pp.4217-4231
05/2016
DOI: 10.1002/2016JA022507
Abstract
The radial and local diffusion processes induced by various plasma waves govern the highly energetic electron dynamics in the Earth's radiation belts, causing distinct characteristics in electron distributions at various energies. In this study, we present our simulation results of the energetic electron evolution during a geomagnetic storm using the University of California, Los Angeles 3‐D diffusion code. Following the plasma sheet electron injections, the electrons at different energy bands detected by the Magnetic Electron Ion Spectrometer (MagEIS) and Relativistic Electron Proton Telescope (REPT) instruments on board the Van Allen Probes exhibit a rapid enhancement followed by a slow diffusive movement in differential energy fluxes, and the radial extent to which electrons can penetrate into depends on energy with closer penetration toward the Earth at lower energies than higher energies. We incorporate radial diffusion, local acceleration, and loss processes due to whistler mode wave observations to perform a 3‐D diffusion simulation. Our simulation results demonstrate that chorus waves cause electron flux increase by more than 1 order of magnitude during the first 18 h, and the subsequent radial extents of the energetic electrons during the storm recovery phase are determined by the coupled radial diffusion and the pitch angle scattering by EMIC waves and plasmaspheric hiss. The radial diffusion caused by ULF waves and local plasma wave scattering are energy dependent, which lead to the observed electron flux variations with energy dependences. This study suggests that plasma wave distributions in the inner magnetosphere are crucial for the energy‐dependent intrusions of several hundred keV to several MeV electrons.
Key Points
Lower energy electrons diffuse closer to the Earth than higher‐energy electrons
Radial diffusion and local plasmaspheric wave scatterings are crucial for the energy‐dependent penetration depths of energetic electrons
Chorus, EMIC, and hiss waves cause their characterized electron pitch angle distributions during the storm recovery phase
Details
- Title: Subtitle
- Simulation of energy‐dependent electron diffusion processes in the Earth's outer radiation belt
- Creators
- C. A Kletzing - University of IowaQ Ma - University of California, Los AngelesW Li - University of California, Los AngelesW. S Kurth - University of IowaR. M Thorne - University of California, Los AngelesG. B Hospodarsky - University of IowaY Nishimura - University of California, Los AngelesX.‐J Zhang - University of CaliforniaG. D Reeves - Los Alamos National LaboratoryM. G Henderson - Los Alamos National LaboratoryH. E Spence - University of New HampshireD. N Baker - University of Colorado BoulderJ. B Blake - The Aerospace CorporationJ. F Fennell - The Aerospace CorporationV Angelopoulos - University of California, Los Angeles
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.121(5), pp.4217-4231
- DOI
- 10.1002/2016JA022507
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 15
- Grant note
- AFOSR NSF (1405054; 1451911) NASA's prime (NAS5‐01072; FA9550‐15‐1‐0158) JHU/APL (967399; 921647) NASA (NNX15AI96G; NNX15AF61G; NNX11AR64G; NNX13AI61G; NNX14AI18G) RBSP‐ECT EMFISIS
- Language
- English
- Date published
- 05/2016
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984200042302771
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