A novel scenario decreasing the saturation level of low-threshold two upper hybrid plasmon parametric decay instability of extraordinary wave

Abstract

The effect of trapping a high harmonic ion Bernstein (IB) wave in a magnetic island possessing a plasma density maximum is predicted. The excitation of these waves in the course of secondary decays leading to saturation of the primary low-threshold two-upper-hybrid-plasmon parametric decay instability of the extraordinary pump wave is investigated. It is shown that the predicted IB wave trapping results in decreasing of the primary instability saturation level. Substantial suppression of the pump wave anomalous absorption due to the IB wave trapping effect is also foreseeing.