Suppression of Self-Excitation in a Plasma Microwave Amplifier with a Coaxial Geometry Using an Extended Microwave Absorber

Abstract

The problem of radiation amplification in a plasma microwave amplifier with a coaxial geometry in the presence of an absorber is considered. The absorber is used to suppress the parasitic feedback, which can lead to self-excitation of the system. At the same time, its presence leads to a modification of its electrodynamic properties. The spatial increments of the beam–plasma instability were calculated, and the parameter ranges where the self-excitation of the amplifier does not occur were determined. The effect of the absorber on the efficiency of the transformation of the kinetic energy of electrons into the energy of microwave oscillations was estimated.