Mode competition in gyrotrons withhighly overmoded cavities can degrade efficiency and output mode purity. One approach to mode selection which has been demonstrated experimentally involves a sudden change in the cavity radius. Cavities with this feature arecalled ‘complex-’ or ‘step-cavities’. This paperpresents a theoretical model for the step-cavity gyrotron. The model applies to the steady state operation. The axial variation of the cavity rf fields is determined self-consistently with the electron beam motion by integration of the wave equation simultaneously with the nonlinear electron equations of motion. The model accounts for mode conversion effects at the step as well as beam loading effects such as cavity Q modification and frequency pulling. The model is applied to the analysis of a TE01/TE04 complex cavitygyrotron.
ASJC Scopus subject areas
- Electrical and Electronic Engineering