Simulation of Sub-THz Backward-Wave Oscillators With a Self-Focused Pseudospark-Sourced Sheet Electron Beam

The results of simulation of the two previously proposed millimeter-band backward-wave oscillators (BWO) driven by a self-focused pseudospark-sourced sheet electron beams are presented. Plasma focusing makes possible beam transmission through a slow-wave structure (SWS) over distances of the order of several cm while providing effective beam-wave interaction. Two models of beam focusing by plasma in SWS are considered. A simplified approach, in which the electrodynamic structure is pre-filled with fully ionized plasma, allows assessing beam transport with effective beam wave interaction. A more accurate model, in which the plasma is formed as a result of impact ionization of the gas by beam electrons allows simulation of non-stationary processes of plasma channel formation. It describes not only plasma focusing in the interaction region, but also the consequent transport of the spent beam to collector via the plasma channel, which remains intact at the exit of the SWS.