Numerical study of relativistic electron beam pumping by virtual cathode

In this article a new method for electron beam pumping by means of virtual cathode is proposed. The electron beam is generated in a foilless diode, whose anode tube is connected directly to a wider output drift tube. The emitted by cold plasma emission from hollow cathode electrons propagate in an external homogeneous magnetic field. The virtual cathode is formed at the wide drift tube entrance. Computer simulations show an essential beam pumping behind the virtual cathode. The transmitted electron beam pitch-ratio ex reaches value above 1 which is sufficient for development of the maser instability.