Nonlinear Electron Interaction With Intense Chorus Waves: Statistics of Occurrence Rates

TitleNonlinear Electron Interaction With Intense Chorus Waves: Statistics of Occurrence Rates
Publication TypeJournal Article
Year of Publication2019
AuthorsZhang, X‐J, Mourenas, D, Artemyev, AV, Angelopoulos, V, Bortnik, J, Thorne, RM, Kurth, WS, Kletzing, CA, Hospodarsky, GB
JournalGeophysical Research Letters
Date Published06/2019
Keywordschorus waves; Electron acceleration; nonlinear wave particle interaction; THEMIS; Van Allen Probes; wave packet size
AbstractA 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 (AE>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.
Short TitleGeophys. Res. Lett.

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