Simulation of energy-dependent electron diffusion processes in the Earth's outer radiation belt

Journal Article · Thu Apr 28 00:00:00 EDT 2016 · Journal of Geophysical Research. Space Physics

DOI:https://doi.org/10.1002/2016JA022507· OSTI ID:1402607

Ma, Q. ^[1]; Li, W. ^[1]; Thorne, R. M. ^[1]; Nishimura, Y. ^[1]; Zhang, X. -J. ^[2]; Reeves, Geoffrey D. ^[3]; Kletzing, C. A. ^[4]; Kurth, W. S. ^[4]; Hospodarsky, G. B. ^[4]; Henderson, M. G. ^[3]; Spence, H. E. ^[5]; Baker, D. N. ^[6]; Blake, J. B. ^[7]; Fennell, J. F. ^[7]; Angelopoulos, V. ^[8]

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1. Univ. of California, Los Angeles, CA (United States). Dept. of Atmospheric and Oceanic Sciences
2. Univ. of California, Los Angeles, CA (United States). Dept. of Atmospheric and Oceanic Sciences; Univ. of California, Los Angeles, CA (United States). Inst. of Geophysics and Planetary Physics/Earth, Planetary and Space Sciences
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
4. Univ. of Iowa, Iowa City, IA (United States). Dept. of Physics and Astronomy
5. Univ. of New Hampshire, Durham, NH (United States). Inst. for the Study of Earth, Oceans, and Space
6. Univ. of Colorado, Boulder, CO (United States). Lab. for Atmospheric and Space Physics
7. Aerospace Corporation, Los Angeles, CA (United States)
8. Univ. of California, Los Angeles, CA (United States). Inst. of Geophysics and Planetary Physics/Earth, Planetary and Space Sciences

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. Here, 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. Lastly, 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.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: National Aeronautic and Space Administration (NASA); National Science Foundation (NSF); USDOE
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1402607
• Report Number(s): LA-UR--16-22083
• Journal Information: Journal of Geophysical Research. Space Physics, Journal Name: Journal of Geophysical Research. Space Physics Journal Issue: 5 Vol. 121; ISSN 2169-9380
• Publisher: American Geophysical Union
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Heliospheric and Magnetospheric Physics
electron acceleration and loss
energy-dependent diffusion
radial diffusion
radiation belt simulation