Effect of Tapered Interelectrode Gap Region on Pseudospark-Sourced Electron Beam Emission

In this article, a comparative experimental and simulations analysis has been carried out to understand the role of tapered gap region on current density and energy of pseudospark (PS)-based electron beam emission. These studies have been performed for 5-gap and 8-gap regions in a tapered multigap multiaperture-based PS electron beam source, keeping the same electron beam fill factor, and other geometrical parameters identical. The source has been operated in a self-breakdown mode. Around four-times increase in the beam current has been observed in the 8-gap case at the fixed applied gap potential ranging between 20 and 25 kV, whereas the tapered interelectrode gap angle has been reduced from 7.5° to 4.5°. The field penetration inside the hollow cathode cavity and tapered region have also been analyzed using simulations, and the obtained results are explained based on built-up space charge in these regions.