A self-consistent field theory for gyrotron oscillators: application to a low<i>Q</i>gyromonotron

Abstract

This paper presents an application of a self-consistent field theory for gyrotron oscillators to a low Q TE01 mode gyromonotron. In this model, the RF field profile function satisfies a wave equation in which the AC beam current appears as a source. The wave equation is solved simultaneously with the electron equations of motion. The results of calculations are compared with experimental data for the efficiency, starting current, and operating frequency. To facilitate a detailed comparison between theory and experiment, data have been taken over a wide range of beam currents and axial magnetic fields. The gyromonotron studied in this work has a tapered cavity structure to enhance efficiency, and a low Q factor to enhance output power. A strong self-consistent field effect is observed in the behaviour of the starting current.