Numerical study of pseudospark discharge based electron beam source for terahertz generation

Summary form only given. Terahertz radiation, which ranges from 0.1 THz to 10 THz, has received substantial interests in recent years. The conventional vacuum electronics technology has the potential to supply high enough powers to underpin many exciting and emerging THz applications. Klystrons have been designed to generate THz radiation. This vacuum device requires a very small sized RF circuit and a very thin electron beam with reasonable beam energy. The pseudospark discharge can provide a suitable high current density and small diameter (< 1 mm) electron beam. In the study of the pseudospark discharge, we have utilized a couple of methods, such as physical analysis and electromagnetic particle-in-cell (PIC) simulations with Monte-Carlo collisions (MCC). The scaling relationship of the electron emission current density corresponding to gas pressure, breakdown voltage, anode-cathode gap distance and cathode materials have been investigated. With the evolution of the time-dependent electric fields, the ionisation of the gas in a pseudospark discharge and the dynamics of the charged particles are studied. The increasing of electron and ion charge as a function of anode-cathode gap separation and gas pressure are also investigated. Through this study, we expect to obtain a fundamental understanding of the pseudospark discharge to generate a high current density small diameter electron beam.