Breakdown Characteristics of Triggered Pseudospark Discharge-Based Multigap Plasma Cathode Electron Source

Abstract

Pseudospark (PS) sourced electron beam with high energy can be produced by a multigap PS discharge-based plasma cathode electron (PD-PCE) source under high-voltage operations. The process of successive high-voltage breakdown and plasma formation inside hollow cathode (HC) and in the gaps play significant role for electron beam generation. An investigation has been carried out for the analysis of discharge processes in different multigap PS structures using the 2-D kinetic plasma simulation code. It has been observed that the distribution of equipotential contour lines in the HC cavity as well as gaps is important to investigate the occurrence of the breakdown and plasma generation in the PD-PCE source. The higher equipotential lines start penetrating through the electrode apertures only when the plasma is formed in the adjacent previous gap. The potential lines help the electrons to run out through the electrode apertures and have collision process for the ionization in the next gaps. The radial expansion of the electrons and ions has also been analyzed which depends on the profile of equipotential contour lines. The expansion of ions is relatively more compared to electrons at the time of breakdown and plasma formation in the gaps. The expansions of electrons and ions are less in the first and last gap compared to the intermediate gaps. The equipotential contour lines determine the successive breakdown and discharge processes in the multigap PD-PCE source, which are required for the generation of efficient plasma, and energetic and high-density PS discharge-based electron beams.