Study on calculation method of terahertz gyrotron with special cross-section cavity

In order to develop high power terahertz sources, high harmonic terahertz gyrotrons with special cross-section cavity have been proposed. The calculation method of the gyrotrons mentioned above has been investigated based on the three-dimensional electromagnetic simulation software CST and traditional nonlinear theory of gyrotrons in this paper. In this method the analytical solution of the high frequency fields is replaced by inserting the simulation results of CST, the beam-wave interaction efficiency, coupling coefficient and starting current have been obtained. A 0.4THz third harmonic TE₃₃ mode gyrotron with corrugated interaction cavity has been designed by making use of this calculation method.