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Nonlinear Electron Interaction With Intense Chorus Waves: Statistics of Occurrence Rates
Author(s) -
Zhang X.J.,
Mourenas D.,
Artemyev A. V.,
Angelopoulos V.,
Bortnik J.,
Thorne R. M.,
Kurth W. S.,
Kletzing C. A.,
Hospodarsky G. B.
Publication year - 2019
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 - 10.1029/2019gl083833
Subject(s) - chorus , van allen radiation belt , physics , electron , nonlinear system , van allen probes , wave packet , amplitude , computational physics , geophysics , plasma , atomic physics , magnetosphere , nuclear physics , quantum mechanics , art , literature
Abstract A comprehensive statistical analysis on 8 years of lower‐band chorus wave packets measured by the Van Allen Probes and THEMIS spacecraft is performed to examine whether, when, and where these waves are above the theoretical threshold for nonlinear resonant wave‐particle interaction. We find that ∼5–30% of all chorus waves interact nonlinearly with ∼30‐ to 300‐keV electrons possessing equatorial pitch angles of >40° in the outer radiation belt, especially during disturbed ( A E >500 nT) periods with energetic particles associated with injections from the plasma sheet. Such considerable occurrence rates of nonlinear interactions imply that the evolution of energetic electron fluxes should be dominated by nonlinear effects, rather than by quasi‐linear diffusion as commonly assumed. We discuss the possible consequences of such a large amount of high‐amplitude chorus waves and examine their characteristics that can influence the efficiency of nonlinear wave‐particle interactions.