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Generation of nonlinear electric field bursts in the outer radiation belt through the parametric decay of whistler waves
Author(s) -
Agapitov O. V.,
Krasnoselskikh V.,
Mozer F. S.,
Artemyev A. V.,
Volokitin A. S.
Publication year - 2015
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 - 10.1002/2015gl064145
Subject(s) - whistler , physics , van allen radiation belt , electron , computational physics , wave packet , instability , wave propagation , acoustic wave , geophysics , optics , atomic physics , magnetic field , mechanics , magnetosphere , quantum mechanics
Huge numbers of different nonlinear structures (double layers, electron holes, nonlinear whistlers, etc., referred to as Time Domain Structures, TDS) have been observed by the electric field experiment on the Van Allen Probes. Some of them are associated with whistler waves. Such TDS often emerge on the forward edges of the whistler wave packets and form chains. The parametric decay of a whistler wave into a whistler wave propagating in the opposite direction and an electron acoustic wave is studied experimentally as well as analytically, using Van Allen Probes data. The resulting electron acoustic wave is considered to be the source of electron scale TDS. The measured parameters of the three waves (two whistlers and the electron acoustic wave) are in good agreement with an assumption of their parametric interaction: ω 0 = ω 1 + ω 2 andk →0=k →1+k →2 . The bicoherence analysis shows the nonlinear nature of the observed electron‐acoustic waves as well as the whistler wave and electron acoustic wave phase relation. The estimated decay instability growth rate shows that the process of three‐wave interaction can develop in a characteristic time smaller than 1 s, thus, the process is rapid enough to explain the observations. This induced parametric interaction can be one of the mechanisms for quasiperiodic TDS generation in the outer Van Allen radiation belt.