Design of a Low-Voltage High-Efficiency 250 GHz Gyrotron

Low-voltage, high-frequency gyrotrons with hundreds watts of power are useful in magnetic resonance spectroscopy and plasma diagnostic applications. In this paper, a 10 kV, 478 W, 250 GHz gyrotron with efficiency near 40% and pitch ratio of 1.5 was designed through linear and nonlinear numerical analysis and Vsim particle-in-cell (PIC) simulation. Vsim is a highly efficient parallel PIC code, but it has seldom been used to carry out electron beam wave interaction simulations of gyro-devices. The setting up of the parameters required for the Vsim simulations of the gyrotron is presented. The results of Vsim simulations agree well with that of nonlinear numerical calculation.