Effects of coherent density fluctuations on the ion–ion hybrid resonance

Abstract

An analytic and numerical study is made of the effects caused by coherent density fluctuations, localized near the ion–ion hybrid resonance, on the propagation and absorption of fast Alfven waves. The system is represented by a Budden equation that incorporates static fluctuations in the ion density profiles. The unperturbed system contains a resonance at x=0 and a cutoff at x=d; the Alfven wave number at resonance is kA. Two cases are considered: fluctuations in the ion concentration ratio η and bulk density fluctuations. When the incident wave directly approaches the resonance, the fluctuation in the concentration ratio δη/η0 is less than 20%, and kAd 1, and concentration fluctuations 2%<δη/η0<5%, enhanced reflection leads to decreased absorption. ...