Numerical Research on a 170-GHz Time-Dependent Multimode Coaxial Gyrotron With Outer Corrugation

In this paper, a coaxial gyrotron with outer corrugation is considered. Its multimode electron equation of motion is derived from the Lorentz equation, and its time-dependent amplitude and phase equation for the TE
_mn
mode is obtained from the wave equation. Using the time-dependent multimode beam-wave interaction equations, the time evolution processes of the time-dependent multimode coaxial cavity gyrotron with outer corrugation are investigated by numerical calculation. Results show that a 170-GHz coaxial gyrotron with outer corrugation can start up and operate stably at the TE
_34,19
mode and its competing modes are suppressed under different initial field amplitude conditions. By the calculation of the time-dependent multimode and single-mode coaxial gyrotron with outer corrugation, it is found that the output power and the output efficiency of the TE
_34,19
mode are 1.856 MW and 32.59%, respectively. These studies show the mode competition processes of the coaxial gyrotron with outer corrugation at the beginning start-up stage.