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Quantifying the relative contributions of substorm injections and chorus waves to the rapid outward extension of electron radiation belt
Author(s) -
Su Zhenpeng,
Zhu Hui,
Xiao Fuliang,
Zheng Huinan,
Wang Yuming,
Zong Q.G.,
He Zhaoguo,
Shen Chao,
Zhang Min,
Wang Shui,
Kletzing C. A.,
Kurth W. S.,
Hospodarsky G. B.,
Spence H. E.,
Reeves G. D.,
Funsten H. O.,
Blake J. B.,
Baker D. N.
Publication year - 2014
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2014ja020709
Subject(s) - substorm , van allen radiation belt , chorus , physics , electron , van allen probes , geophysics , flux (metallurgy) , radiation , magnetosphere , computational physics , nuclear physics , plasma , chemistry , art , literature , organic chemistry
We study the rapid outward extension of the electron radiation belt on a timescale of several hours during three events observed by Radiation Belt Storm Probes and Time History of Events and Macroscale Interactions during Substorms satellites and particularly quantify the contributions of substorm injections and chorus waves to the electron flux enhancement near the outer boundary of radiation belt. A comprehensive analysis including both observations and simulations is performed for the first event on 26 May 2013. The outer boundary of electron radiation belt moved from L = 5.5 to L > 6.07 over about 6 h, with up to 4 orders of magnitude enhancement in the 30 keV to 5 MeV electron fluxes at L = 6. The observations show that the substorm injection can cause 100% and 20% of the total subrelativistic (∼0.1 MeV) and relativistic (2–5 MeV) electron flux enhancements within a few minutes. The data‐driven simulation supports that the strong chorus waves can yield 60%–80% of the total energetic (0.2–5.0 MeV) electron flux enhancement within about 6 h. Some simple analyses are further given for the other two events on 2 and 29 June 2013, in which the contributions of substorm injections and chorus waves are shown to be qualitatively comparable to those for the first event. These results clearly illustrate the respective importance of substorm injections and chorus waves for the evolution of radiation belt electrons at different energies on a relatively short timescale.