Journal article
Diffusive Transport of Several Hundred keV Electrons in the Earth's Slot Region
Journal of geophysical research. Space physics, Vol.122(10), pp.10,235-10,246
10/2017
DOI: 10.1002/2017JA024452
Abstract
We investigate the gradual diffusion of energetic electrons from the inner edge of the outer radiation belt into the slot region. The Van Allen Probes observed slow inward diffusion and decay of ~200–600 keV electrons following the intense geomagnetic storm that occurred on 17 March 2013. During the 10 day nondisturbed period following the storm, the peak of electron fluxes gradually moved from L ~ 2.7 to L ~ 2.4, and the flux levels decreased by a factor of ~2–4 depending on the electron energy. We simulated the radial intrusion and decay of electrons using a three‐dimensional diffusion code, which reproduced the energy‐dependent transport of electrons from ~100 keV to 1 MeV in the slot region. At energies of 100–200 keV, the electrons experience fast transport across the slot region due to the dominance of radial diffusion; at energies of 200–600 keV, the electrons gradually diffuse and decay in the slot region due to the comparable rate of radial diffusion and pitch angle scattering by plasmaspheric hiss; at energies of E > 700 keV, the electrons stopped diffusing near the inner edge of outer radiation belt due to the dominant pitch angle scattering loss. In addition to plasmaspheric hiss, magnetosonic waves and VLF transmitters can cause the loss of high pitch angle electrons, relaxing the sharp “top‐hat” shaped pitch angle distributions created by plasmaspheric hiss. Our simulation indicates the importance of balance between radial diffusion and loss through pitch angle scattering in forming the diffusive intrusion of energetic electrons across the slot region.
Key Points
The observed 10 day diffusive evolution of several hundred keV electrons in the slot region is simulated using a 3‐D diffusion model
The energy‐dependent intrusion and decay are caused by the competition between radial diffusion and pitch angle scattering
Magnetosonic waves and VLF transmitters relax the “top‐hat” shaped pitch angle distributions of energetic electrons created by hiss waves
Details
- Title: Subtitle
- Diffusive Transport of Several Hundred keV Electrons in the Earth's Slot Region
- Creators
- Q Ma - Boston UniversityW Li - Boston UniversityR. M Thorne - University of California, Los AngelesJ Bortnik - University of California, Los AngelesG. D Reeves - Los Alamos National LaboratoryH. E Spence - University of New HampshireD. L Turner - The Aerospace CorporationJ. B Blake - The Aerospace CorporationJ. F Fennell - The Aerospace CorporationS. G Claudepierre - The Aerospace CorporationC. A Kletzing - University of IowaW. S Kurth - University of IowaG. B Hospodarsky - University of IowaD. N Baker - University of Colorado Boulder
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.122(10), pp.10,235-10,246
- DOI
- 10.1002/2017JA024452
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 12
- Grant note
- AFOSR (FA9550‐15‐1‐0158) NASA's prime (NAS5‐01072) EMFISIS (1001057397:01) JHU/APL (967399; 921647) NSF (AGS‐1723588) ECT (13‐041) NASA (NNX17AD15G; NNX17AG07G; NNX14AN85G)
- Language
- English
- Date published
- 10/2017
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199798902771
Metrics
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