Multimode Analysis of A Dual Electron-Beam Quasi-Optical Gyrotron

A multimode analysis has been carried out to clarify growing frequencies of a 1-MW, 150-GHz dual electron-beam quasi-optical gyrotron oscillator, with a cavity resonator composed of two coaxial annular mirrors. The results show that the gyrotron can be operated at a single frequency with a fundamental mode in the azimuthal direction for the present range of parameters. Its achievable efficiency is 40% when the magnetic field of the cavity is shifted after the operation mode is grown up.