Problems and advances of high power gyrotron

The paper reviews some problems of high power gyrotrons, especially related to mode selection and the provision of stability of a high-efficiency operating mode in oversized resonators and the possible solution. Results of calculation and an experimental study of gyrotrons operating in a wide frequency,range and at the 1 MW power level are presented. The effects of beam potential depression in gyrotrons, effects of mode interaction (competition and cooperation) and methods of mode selection, including multibeam and complex cavity systems, are presented. The dependence of gyrotron parameters on the beam current and magnetic field is analyzed. The experimental results are compared with the calculated data.