Numerical analysis of the influence of reflections on gyrotron operation

The results of a newly developed self-consistent time-domain (TD) analysis of gyrotron operation in the presence of reflections are reported. The influence of reflections of different kind on the operation of a 1 MW, 140 GHz, TE/sub 22,6/-mode gyrotron has been investigated numerically for a wide range of parameters. In some cases, this investigation demonstrates an unstable behavior of the gyrotron oscillator whose output signal shows a broad spectrum up to about 12% of relative width. The numerical results agree well with results obtained from an experimental gyrotron at Forschungszentrum Karlsruhe.