Influence of Controlled Reflected Power on Gyrotron Performance

This paper describes the reaction of a gyrotron oscillator when a very small fraction of its radiation, extracted from the main beam, is phase-modulated in a controlled way and is finally redirected back to the gyrotron. The gyrotron may exhibit a 10 % modulation of its total power even if the reflected power is lower than 1 %. Moreover, radial probing of the beam power distribution shows that the amplitude of the power modulation differs at different radial positions across the beam.