Studies on influence of seed electrons and physical dimensions of hollow cathode on Pseudospark discharge

Abstract

Pseudospark discharge is a specific type of gas discharge, which operates on the left-hand side of the hollow cathode analogy to the Paschen curve with axially symmetric parallel electrodes and central holes on the electrodes [1-2]. The discharge is characterized by a very rapid breakdown phase; during which high-density particle beams can be extracted and rapid increasing rate of current can be achieved. The initiation phase of Pseudospark discharges is very important in the whole hollow cathode discharge procedure because of it has direct influence to parameters of discharge current, stability, pulse width, amplitude, switching time and so on. The theoretical studies of the Pseudospark discharges have been carried out. A theoretical and plasma simulation model has been adopted to study the initiation phase of Pseudospark discharges. The pre-breakdown and breakdown phases of a Pseudospark discharge are investigated using the two-dimensional kinetic plasma simulation code OOPIC Pro [3].Trends in the electron density at the anode are presented as function of the hollow cathode dimensions and mean seed injection velocities at the cavity back wall. The plasma generation process by ionizing collisions is examined, showing the effect on supplying electrons that determine the density of the beam. The growth phenomena is dependent on the Townsend coefficient due to local space charge from initial ionization growth to onset of the hollow cathode effect, and then hollow cathode effect become leading factor. The experiment has also been performed for the analysis of the pseudospark discharge Fig (1): Simulation Model, Full Sectional View of single gap PSS, Paschen curveTo investigate the geometrical effect of electrodes in hollow cathode. We consider two cases of energy for simulation. Case (1) vx =1000 and emitter current 10 amp. With a temperature 2.5 eV and injection period 1 ns. Case (2): vx=500 and emitter current 4 amp. With a temperature 1.5 eV and injection period 100 ns. In these cases the discharge is filled with Hydrogen gas at room temperature and at a pressure of approximately 35 Pascal with an anode voltage 10 kV and a grounded cathode.

Experimental Analysis of Pseudospark Sourced Electron Beam

“…Studies have been done on the influence of seed electrons and physical dimension of hollow cathode on pseudospark discharge [3,4]. By PCE gun it means a system that serves as a source for electron beam that is formed by extraction from plasma.…”