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

Author
Keywords
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\textendash30\% of all chorus waves interact nonlinearly with \~30- to 300-keV electrons possessing equatorial pitch angles of >40\textdegree 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.
Year of Publication
2019
Journal
Geophysical Research Letters
Date Published
06/2019
ISSN Number
0094-8276
URL
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083833
DOI
10.1029/2019GL083833