To the theory of gyrotrons with confocal resonators

Abstract

In recent years, in addition to the development of traditional gyrotrons with an axially symmetric interaction space, there has been strong interest in developing gyrotrons, whose interaction space is not axially symmetric (e.g., gyrotrons with confocal resonators). The theory of such gyrotrons is presented in this paper. First, equations describing such gyrotrons in the cold-cavity approximation are formulated. Then, the linear theory is developed, which is followed by a simple, single-mode, nonlinear theory. After that, the theory describing the mode interaction in such gyrotrons is presented. Then, an alternative concept of gyrotrons with single and multicavity confocal resonators and sheet electron beams is proposed. This paper also includes the analysis of diffractive losses in confocal resonators and the estimates for curling of the ends of sheet beams of gyrating electrons caused by the space charge forces.