Properties of a differential pressure pseudospark device

Abstract

A differential pressure pseudospark device is developed to produce a discharge at a pressure of 10^-4mbar near the anode. This pressure range is two orders in magnitude lower than conventional pseudospark devices. In this device a pressure gradient is maintained between the cathode and the anode by providing a gas flow through the discharge column. The pressure gradient helps in shifting the Paschen curve more towards the left in comparison to the conventional case. The empirical relationship V∞ (p²dD)^-2, valid without a gas flow, is not applicable when the pressure difference between the cathode and the anode is over two orders in magnitude. Self-biasing collector technique reveals the presence of energetic electrons (0.4-1.2 keV) present in the plasma downstream of the anode. The nature of this plasma at two distinct pressure ranges of operation of the device shows marked difference in properties. A qualitative discussion is presented that explains the possible discharge mechanism in this device.