Multimode simulation of the frequency spectrum of a quasi-optical gryrotron

Abstract

We have performed a multimode simulation of the frequency spectrum of a quasi-optical 120 GHz gyrotron with a small mirror separation (d = 5 cm) which, therefore, presents a large separation between the frequencies of the modes (δω/ω= 2 · 5%). It appears that under this condition multimode equilibrium is quite frequent. However, even if single mode equilibrium is not achieved, the electronic efficiency η remains high: under all magnetic field profiles its maximum reaches about 30%, and is equal to or exceeds the maximum single mode efficiency.