A moderately relativistic subgigawatt microwave oscillator of twistron type operating with 50% efficiency

A regime of quasi-stationary microwave generation in moderately relativistic microwave oscillator of the twistron type with 50 $\pm$ 20% efficiency of electron beam power conversion into electromagnetic radiation has been obtained in experiment through optimization of the electron–wave interaction. For the selected electron beam parameters (diode voltage, 210 kV; beam current. 1.36 kA) the output microwave power at 10.63 GHz frequency was 140 $\pm$ 40 MW in a guiding magnetic field of about 1.9 T. The duration of microwave pulses was about 16 ns.