Electron beam and Cherenkov interaction experiments based on pseudospark discharge

In this paper we have presented measurements of coherent electromagnetic radiation generation in a free electron maser using an electron beam from a pseudospark discharge. A 100 A, 40 kV electron beam pulse was measured at a distance of 120 mm from the acceleration gap without a magnetic guiding field. Comparing this with the simulation implies that a favourable ion background exists along the beam channel and the acceleration gap. The ion background can be formed from the background gas ionization by the initial high energy hollow cathode phase (HCP) beam during the pseudospark discharge, which also expels electrons in the ionized gas media.