Self-Consistent Post-Amplification of a Gyrotron RF Beam by a Sheet Electron Beam

Abstract

The availability of high power gyrotrons makes it possible to use the Gaussian output RF beam as input for the interaction with a sheet electron beam, with the aim of generating even higher RF power. Since this interaction is from the beginning in the high‐efficiency nonlinear regime, it can proceed without the need of a resonator and without the restrictions of mode competition inherent in a quasi‐optical gyrotron arrangement. The nonlinearly perturbed electron trajectories have been tabulated, as function of field amplitude and frequency mismatch, as the first step to an iterative self‐consistency scheme. In addition, the radiation fields from the nonlinearly perturbed electrons are calculated, under an assumed longitudinal profile of the RF fields. This second step is to be repeated, until convergence is achieved. The first results show that the radiated fields indeed have a Gaussian cross‐section, so that it can be reasonably expected that they can add constructively to the initial input.