Abstract :
Experimental investigations of Cherenkov plasma amplifier have been carried out. The dependencies of output microwave power on plasma density, interaction length, input microwave power, relativistic electron beam current, and input signal frequency were measured. A pure amplification regime (without accompanying generation) at two frequencies of 9.1 and 13 GHz is achieved. It is shown experimentally that there is a range of plasma densities where the only azimuthally-symmetric plasma waveguide mode with the lowest radial index is excited. The relative bandwidth of the amplifier, according to the experiment, is no less than 40 %. It is experimentally shown that, by changing only one parameter, namely, the plasma density, is possible to achieve maximum output microwave power at any of two frequencies - 9.1 and 13 GHz. 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).
Keywords :
amplification; microwave power amplifiers; plasma density; plasma devices; plasma diagnostics; plasma filled waveguides; plasma transport processes; relativistic plasmas; Cherenkov plasma amplifier; amplification regime; azimuthally-symmetric plasma waveguide mode; frequency 13 GHz; frequency 9.1 GHz; input microwave power; input signal frequency; interaction length; output microwave power; plasma density; power gain; relativistic electron beam current; Detectors; Lead; Magnetrons;