Pre-breakdown processes in the hollow cathode region of a transient hollowcathode discharge

Discharge formation in the A-K space of transient hollow cathode discharge (THCD) is causally linked with the emission of high energy electron beams o riginating in the hollow cathode region (HCR). Ionization in the A-K gap pr oceeds through the formation of a moving virtual anode, whose time evolutio n is strongly correlated with different periods in the electron beam activi ty. Here, we report on time and space resolved observations of different io nization events inside the HCR, which are time correlated with ionization p rocesses inside the A-K gap. The experiments have been performed in Hydroge n, at pressures between 50 and 400 mTorr. A statistical study of the charac teristic times associated with the different ionization events, based on vo n Laue plots, shows that the time distribution of events is well described by a single Gaussian distribution.