Transient and nonlinear behavior of absolute instability in finite-length CARM

Abstract

A theoretical analysis is presented which is capable of predicting the starting oscillation condition and the temporal growth rate of the absolute instability in a finite-length cyclotron autoresonance maser system. The theoretical prediction is confirmed by computer simulations. The nonlinear saturation mechanism is observed to be due to the electron nonlinear phase shift induced by the wave field which tends to shorten the effective interaction length and brings the system into the marginally stable state.