Breakdown formation in a transient hollow cathode discharge-a statistical study

Discharge formation at low pressure is found to be greatly influenced in the presence of a suitable hollow cathode region. The formation of a moving virtual anode which extends the anode potential to within the hollow cathode region is thought to be responsible for the enhanced ionization growth which subsequently leads to gas breakdown. In this paper, the spatial evolution of the local potential in the discharge region of a pulsed hollow cathode discharge has been measured in a range of pressures with two different cathode apertures. An extensive data set has been collected and analyzed using a statistical technique. From the characteristic of the statistical distribution of the data, unique features associated with the role of hollow cathode at the different stages of discharge formation have been identified. It was found that the influence of the hollow cathode region is strongest in the start of ionization growth and in the final change over to high current breakdown