Influence of the Injection Speeds on the Discharge Characteristics and Minimization of Delay Time in a Pseudospark Discharge

Abstract

The study put forth demonstrates that the seed electrons average kinetic energy influences the discharge characteristics making it possible to maximize the rate of development of the virtual anode in a pseudospark, with a suitable choice of the neutral gas pressure as determined by the seed's average injection speed. This investigation also brings to light two distinct operating regimes; (1) mid-energy, where electron-impact ionization energy losses result in a decrease in the cross-section as the electrons travel downstream and (2) high-energy, where, in contrast, the ionization cross-section increases. In the latter case, both the fastest delay time and the neutral gas pressure producing this value have linear dependencies on the seed electrons energy resulting in a constant value of their product over the different injection speeds. The discharge is seeded by injecting a current pulse for a period of one nanosecond along the axis from the hollow cathode cavity back wall over a range of mean speeds corresponding to 100 to 900 V accelerations; the initial electric field is insufficient to enhance ionization throughout most of the hollow cathode backspace. Data is obtained through computer simulation using the two-dimensional kinetic plasma code OOPIC Pro. 51.50.+v, 52.75.Kq, 52.80.Tn.