Numerical study of a 170-GHz, gradient-cavity gyrotron

Summary form only given. How to improve the efficiency of the gyrotron is always the focus of attention in studying gyrotron. There are many way to enhance the efficiency of the gyrotron, which are mainly concentrated in two aspects, one is designing the gyrotron with a depressed collector, the another is by changing the cavity structure to improve efficiency. In the paper, we adopt a new cavity structure which can better inhibit mode competition and get higher coupling efficiency, the gyrotron with the new cavity has been optimized and simulated. An output power more than 1.5 MW is obtained at the accelerating beam voltage of 80 kV, the beam current of 45 A, the transverse-to-axial velocity ratio of 1.3, corresponding to the overall efficiency of 47.2%.In order to further verify the new design of tube, the hot cavity should be simulated adequately. Through numerical simulation, we finally determine the working parameters as follows: The accelerating beam voltage of 80 kV, the beam pitch ratio of 1.3, the beam current of 45 A, the efficiency of 47.12%, the power of above 1.5 MW.