Beam instability in a plasma microwave amplifier with an absorber

The beam-plasma instability development in a plasma microwave amplifier with an absorber uniform along the length of the system is considered. The addition of an absorber to the system is due to the need to suppress parasitic feedback. In this case, the presence of an absorber leads to a modification of the system's electrodynamic properties. Increments of beam-plasma instability are calculated, and parameter regions are determined when self-excitation of the amplifier does not occur. Efficiency of conversion of electron energy into energy of the amplified waves and the effect of absorber on it are estimated.