The recent development of high-voltage pulse technology has resulted in possibility for production of charge particle beams with currents in excess of 10 kA at accelerating voltages of several hundred kV and more. When such an intense electron beam propagates inside an evacuated conducting drift tube under certain conditions the non-neutralized beam space-charge leads to the formation of virtual cathode. The virtual cathode phenomenon can be used for ion acceleration or high-power microwave generation. The process of virtual cathode formation and the emission of microwave radiation at gigahertz frequencies by virtual cathode have been investigated using computer simulation.
