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Quantifying Extremely Rapid Flux Enhancements of Radiation Belt Relativistic Electrons Associated With Radial Diffusion
Author(s) -
Liu Si,
Yan Qi,
Yang Chang,
Zhou Qinghua,
He Zhaoguo,
He Yihua,
Gao Zhonglei,
Xiao Fuliang
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl076513
Subject(s) - van allen radiation belt , electron , physics , chorus , van allen probes , diffusion , flux (metallurgy) , radiation , computational physics , atomic physics , ion , magnetosphere , astrophysics , plasma , nuclear physics , materials science , art , literature , quantum mechanics , metallurgy , thermodynamics
Previous studies have revealed a typical picture that seed electrons are transported inward under the drive of radial diffusion and then accelerated via chorus to relativistic energies. Here we show a potentially different process during the 2–3 October 2013 storm when Van Allen Probes observed extremely rapid (by about 50 times in 2 h) flux enhancements of relativistic (1.8–3.4 MeV) electrons but without distinct chorus at lower L ‐shells. Meanwhile, Time History of Events and Macroscale Interactions during Substorms satellites simultaneously measured enhanced chorus and fluxes of energetic (∼100–300 keV) seed electrons at higher L ‐shells. Numerical calculations show that chorus can efficiently accelerate seed electrons at L ∼ 8.3. Then radial diffusion further increased the phase space density of relativistic electrons throughout the outer radiation belts, with a remarkable agreement with the observation in magnitude and timescale. The current results provide a different physical scenario on the interplay between radial diffusion and local acceleration in outer radiation belt.