A 50-MW broadband plasma microwave amplifier

A pure amplification regime (without accompanying generation) at two frequencies of 9.1 and 13 GHz is achieved in a plasma relativistic microwave amplifier. It is shown experimentally that an amplification regime with an output power of 40 MW can be achieved at both frequencies without changing the parameters of the system. This fact, along with the results of calculations, allows one to assert that the relative bandwidth of the amplifier is no less than 40%. It is shown experimentally that, by changing only one parameter, namely, the plasma density, the frequency corresponding to the maximum amplification can be varied from 9.1 to 13 GHz, which agrees with the results of calculations by a nonlinear model. At a frequency of 9.1 GHz, the maximum output power amounts to P = 40 MW, the efficiency is η 4%, and the power gain is Kp = 800 (29 dB). At a frequency of 13 GHz, these parameters are P = 60 MW, η = 6%, and Kp = 1000 (30 dB). The measured plasma density range in which the amplification is observed agrees with calculations of the excitation of an E01 mode of a plasma waveguide