Alfvén Wave Amplification as a Result of Parametric Quasi-Resonant Interaction with Magnetoacoustic Waves in Heat-Releasing Isentropically Unstable Plasma

Abstract

Quasi-resonant parametric decay of a magnetoacoustic wave into two Alfvén waves in a heat-releasing plasma is considered. It is shown that in the case of isentropical instability under the resonant conditions (zero frequency detuning) the Alfvén waves undergo bi-exponential amplification. The presence of frequency detuning prior to this amplification gives rise to parametric modulation of the Alfvén wave amplitude, whose duration increases with detuning. A boundary frequency detuning is determined, at which there is no amplification of the Alfvén waves.