2024-03-28T10:02:18Z
https://nagoya.repo.nii.ac.jp/oai
oai:nagoya.repo.nii.ac.jp:00022997
2023-01-16T04:12:36Z
336:695:696
Rapid increase in relativistic electron flux controlled by nonlinear phase trapping of whistler chorus elements
Saito, Shinji
67954
Miyoshi, Yoshizumi
67955
Seki, Kanako
67956
Wave-particle interactions with whistler chorus waves are believed to provide a primary acceleration for electrons in the outer radiation belt. Previous models for flux enhancement of the radiation belt have assumed the stochastic process as a diffusion manner of successive random-phase interactions, but physical mechanisms for the acceleration are not fully incorporated in these models because of the lack of a nonlinear scattering process. Here we report rapid increase in relativistic electron flux by using an innovative computer simulation model that incorporates not only diffusive process but also nonlinear scattering processes. The simulations show that three types of scattering simultaneously occur, which are diffusive, phase trapping, and phase bunching. It is found that the phase trapping is the most efficient mechanism to produce the MeV electrons rapidly in the scattering processes. The electrons are accelerated from 400 keV to over 1 MeV in time scale less than 60 s. On the other hand, as the phase trapping is suppressed by the breaking of relative phase angle between waves and gyrating electrons during the interaction, the increase of electron flux at MeV energy is clearly reduced. Our simulations conclude that the phase-trapping process causes a significant effect for the increase in relativistic electron flux and suggest that a quasi-linear diffusion model is not always valid to fully describe the relativistic electron acceleration.
journal article
Wiley
2016-07-23
application/pdf
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
7
121
6573
6589
http://doi.org/10.1002/2016JA022696
http://hdl.handle.net/2237/25181
2169-9356
https://nagoya.repo.nii.ac.jp/record/22997/files/Saito_et_al-2016-Journal_of_Geophysical_Research_Space_Physics.pdf
eng
https://doi.org/10.1002/2016JA022696
© 2016 American Geophysical Union