Numerical study and simulation of a 170Â GHz megawatt-level corrugated coaxial-gyrotron

As the sources of high-power microwave and terahertz, gyrotrons have important development prospects. However, there are many difficulties to be resolved in study and design of gyrotrons meeting requirements. In this paper, the beam-wave interactions of a 170 GHz megawatt-level corrugated coaxial-gyrotron are studied numerically. In order to attain high efficiency and stable radiation, TE31,12 mode that lies in a relative sparse spectrum is selected as the operating mode and the beam-wave coupling coefficient, and start oscillation current are calculated by a set of source codes. Taking into account electronic velocity spread, and cavity wall resistivity and basing on single-mode approximation, the optimized design and simulation of beam-wave interaction of a 170 GHz MW corrugated coaxial-gyrotron have be fulfilled. The relationships between the efficiency and magnetic field, voltage, current, and parameters of groove are presented. The results show that voltage and magnetic field have great influences on efficiency, but the current and velocity spread do slightly, so reduce the requirements of electronic gun design. In addition, the optimized geometry parameters can improve efficiency, reduce the impact of velocity spread on efficiency, and achieve around 48.6% electronic efficiency and 1.7 MW output power at 5% velocity spread, and 6.896 × 10−8 Ω m resistivity.