Influences of distributed losses on start current, quality factor Q and frequency in multi-mode multi-frequency coaxial gyrotrons

Abstract

The primary problem that gyrotrons encounter is mode competition during their development, especially multi-mode multi-frequency gyrotrons. In this paper, the influence of distributed losses on start current, quality factor Q and resonant frequency were studied. Four types of distributed losses are discussed, which each type can also increase start oscillation current of operating and competing modes. But the amplitudes of increase are different, which makes the start oscillation current of operating and competing modes further separated. By separating start oscillation currents, they suppress competing modes and enhance devices stability. The adverse effect of distributed losses is that they reduced Q value and raised resonant frequency slightly. But they have little effect on other performance of gyrotrons. The start oscillation current of multi-mode multi-frequency coaxial gyrotrons with distributed losses has the ability to suppress mode competition and improve stability of operation. So it is a new method of suppressing modes competition that deserves consideration.