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Title: On the Physical Mechanisms Driving the Different Deep Penetration of Radiation Belt Electrons and Protons
Abstract During active geomagnetic periods both electrons and protons in the outer radiation belt have been frequently observed to penetrate to lowL(<4). Previous studies have demonstrated systematic differences in the deep penetration of the two species of particles, most notably that the penetration of protons is observed less frequently than for electrons of the same energies. A recent study by Mei et al. (2023,https://doi.org/10.1029/2022GL101921) showed that the time‐varying convection electric field contributes to the deeper penetration of low‐energy electrons and that a radial diffusion‐convection model can be used to reproduce the storm‐time penetration of lower‐energy electrons to lowerL. In this study, we analyze and provide physical explanations for the different behaviors of electrons and protons in terms of their penetration depth to lowL. A radial diffusion‐convection model is applied for the two species with coefficients that are adjusted according to the mass‐dependent relativistic effects on electron and proton drift velocity, and the different loss mechanisms included for each species. Electromagnetic ion cyclotron (EMIC) wave scattering losses for 100s of keV protons during a specific event are modeled and quantified; the results suggest that EMIC waves interacting with protons of lower energies than electrons can contribute to prevent the inward transport of the protons.  more » « less
Award ID(s):
2140934 2338125 2131012
PAR ID:
10543297
Author(s) / Creator(s):
; ; ; ; ; ;
Publisher / Repository:
Wiley
Date Published:
Journal Name:
Journal of Geophysical Research: Space Physics
Volume:
129
Issue:
8
ISSN:
2169-9380
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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