Impact of Irregular Electrode Apertures in Multigap Pseudospark Discharge Geometries for the Generation of High Density and Energetic Electron Beams

In this article, a multigap pseudospark (PS) discharge-based plasma cathode electron (PD-PCE) source is considered for the generation of high density and energetic pulsed electron beams using electrostatic 2-D kinetic particle-in-cell (PIC) simulation code OOPIC Pro. The characteristics of the generated electron beams are very much dependent on the geometrical and operating parameters of PD-PCE source. The size, uniformities, and irregularities of electrode apertures play a significant role on the generation of high density and energetic electron beams. Investigation has been carried out to analyze the effect of the irregular electrode apertures in PD-PCE source for the generation of electron beams. The combinations of irregularities considered in the diameter of electrode apertures are 2, 4, 6, and 8 mm, mostly used for the development of PD-PCE sources. It has been observed that the aperture size of first electrode decides the delay in breakdown of first gap at constant operating conditions. The delay primarily depends on the penetrating behavior of equipotential lines which leads the successive breakdowns in the remaining gaps of multigap PD-PCE source. The latter electrodes of multigap geometry are responsible for guiding the size of electron beams. Dips in the electron beam currents have been observed during its rise, which are dependent on the sequence of irregular electrode apertures and operating conditions. The gas pressure and electrode apertures control the voltage falls in gaps and rise of electron beam current. The study would support the design and the development of PD-PCE sources suitable for extreme ultraviolet (EUV)/soft X-ray, microwave, and surface modification applications.