Impact of trapped waves radiation losses on the saturation of low threshold two-UH-plasmon parametric decay instability

Abstract

Abstract The dispersion equation for metastable states in a finite tower of eigenmodes of trapped upper hybrid (UH) waves arising from a non-monotonic density profile is derived and then solved both analytically and numerically. The influence of the UH eigenmode damping due to the radiation losses on the saturation level of the two-UH-plasmon low-threshold parametric decay instability is analyzed. Transitions from the odd-step number secondary decay saturation cascade to the even one and vice versa at the radiation loss variation are investigated and shown to initiate a substantial change of the anomalous absorption.