Design of interaction cavity of a 170-GHz, 1-MW gyrotron for ECRH application

The design of the interaction cavity of a 170 GHz gyrotron operating in the TE34,10 mode is presented in this article. An in-house developed code GCOMS and Particle-in-Cell (PIC) code MAGIC are used for the mode selection and beam–wave interaction simulations, respectively. The cold cavity analysis and beam–wave interaction computation are carried out to analyze the eigenmode and output power, respectively. A thorough parametric analysis of the interaction cavity geometry and electron beam parameters is also carried out with respect to the output power and frequency. The results show the capability of the interaction cavity, designed for the TE34,10 mode, to produce more than 1 MW of RF power of a gyrotron at the operating frequency of 170.03 GHz.

► Particle-in-cell (PIC) numerical approach is used for beam–wave interaction for 1 MW/170 GHz gyrotron.
► TE34,10 is selected as the operating mode as it show less mode competition compare to the other high order modes.
► The interaction efficiency is 38% without depressed collector.
►  The power and resonant frequency stable at 625 ns for this interaction cavity.
► Vast numerical calculations related to parametric study is presented.