Relativistic BWO with Short Interaction Space

Summary form only given. The results of experimental investigations of two high power relativistic BWOs with short electrodynamic systems and input reflectors that convert an operating wave to a wave extracting radiation from the interaction space, and modulate the electron beam are presented. A variation of the quasi-static potential of the electron beam takes place in the section with deep corrugation of the waveguide wall. This variation significantly alters phase relations and the magnitude of coupling between interacting waves. In the experiments amplitude and phase relations are chosen by varying the length of the drift channel between the reflector and the interaction space and by applying resonant modulators. We have used a system of coupled cavities or a Bragg reflector as a resonant modulator. We also demonstrate that these gigawatt BWO-oscillators can work at high repetition rate and with low impedance (down to 50 Omega) electron beams.