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

The availability of high-power microwave sources like gyrotrons makes it now possible to use the Gaussian output RF beam of a conventional gyrotron propagating in free space as an input for the interaction with a sheet electron beam (e-beam) drifting along an external magnetic field, with the aim of generating even higher RF power. Since this interaction is from the beginning in the nonlinear high-efficiency regime, the corresponding field amplitude is adequate to extract a significant amount of power from the high-current e-beam with no need for feedback from the walls of any cavity or resonator. The radiation field excited by the nonlinear perturbed electron motion has been calculated using a self-consistent iterative scheme and is seen to maintain the basic features of the initial RF beam (such as the Gaussian profile), but at a much higher power level as is desired for a fusion reactor.