Theoretical investigation of anomalously high efficiency in a three cavity gyroklystron amplifier

The University of Maryland´s three cavity gyroklystron amplifier operating at a frequency of 10 GHz, voltage of 425 kV, current of 160 A, and pitch angle (ν⊥/νz) near. 82, has demonstrated an efficiency of 35%. Our simulations using fixed field profiles predict a significantly lower efficiency, primarily because of the small pitch angle in the experiment. We will be investigating two methods of improving the efficiency in our simulations: beam-wave interaction after the output cavity, and modification of the first two cavity Qs due to beam loading. Results of our nonlinear code will be given for both cases.