Open AccessOn nonlinear decay of kinetic Alfvén waves and application to some processes in space plasmas
Author(s) -
Zhao J. S.,
Wu D. J.,
Lu J. Y.
Publication year - 2010
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010ja015630
Subject(s) - physics , gyroradius , kinetic energy , instability , alfvén wave , electron , wavelength , computational physics , plasma , gyrokinetics , atomic physics , classical mechanics , magnetohydrodynamics , nuclear physics , mechanics , optics , tokamak
This paper considers the nonlinear decay of the kinetic Alfvén waves (KAW) in the space plasmas. By using a two‐fluid model, we obtain a nonlinear equation to investigate the resonant interaction among three kinetic Alfvén waves. It is shown that the parametric instability of the kinetic Alfvén wave becomes important when its perpendicular wavelength is the order of the ion acoustic gyroradius or the electron inertial length. We give a detailed discussion for the KAW decay in the plasma inertial range and show that (1) the reverse decay of the kinetic Alfvén wave is stronger than its parallel decay for the arbitrary wavelength range; (2) the reverse decay is lager than the parallel decay for small angles of two perpendicular wave vectors of the decay waves, and these two decays are zero for large angles; (3) both growth rates depend on the choice of the wave number range of the decay waves; and (4) there exists two forbidden regions for the KAW decay. In this paper, we also discuss the nonlinear decay of the kinetic Alfvén waves in the auroral zone and show that the parametric instability can occur there and may play an important role in forming two reverse electron streaming fluxes in the electron acceleration region.