Breakdown characteristics of Argon in partial vacuum under kHz pulsed voltage for point-to-point electrode geometry

Power devices and systems operating in partial vacuum environment are usually susceptible to partial discharges, corona, or volume discharge, more than the ones operating in atmospheric conditions. In most cases, it is important to understand the characteristics of the discharge such as the space-charge distribution, the electron energy distribution, and collision processes in which the species are involved. Breakdown and spectroscopic studies of the discharge are the most commonly used methods of obtaining such information. In this paper, the breakdown characteristics of Argon for the point-to-point electrode geometry under partial vacuum of 0.1 Torr to 3 Torr, for kHz and dc applied fields are presented. A unipolar pulsed signal at frequencies from 20-220 kHz is applied to electrodes, and the breakdown voltage vs pressure data is recorded. This data is compared with the dc breakdown data under the same experimental conditions. Breakdown voltage as a function of frequency for three different pressure values, namely 0.4 Torr (the minimum breakdown voltage), 0.8 Torr, and 1.2 Torr also recorded to demonstrate the frequency effects on the breakdown voltage. Furthermore, three different frequencies, namely 20 kHz, 50 kHz, and 100 kHz with varying duty cycle from 10% to 90% are used in the experiments to determine the duty cycle effects on the breakdown voltage. For these experiments the pressure is kept at a constant. Current-voltage, optical emission waveforms, and optical spectroscopic data of the argon discharge, collected as a function of time, are presented also.