Properties of a laser-initiated pseudospark discharge

A short-pulse Nd:YAG laser is used to illuminate the back electrode surface in the hollow cathode region of a pseudospark discharge. A fast rising step voltage pulse is applied across the electrodes at various times relative to the pulsed laser illumination. The delay and jitter to the onset of gas breakdown at various filling gas pressures are measured for different laser energies and wavelengths. It is observed that the millijoule range of a green laser applied to illuminate the hollow cathode surface at up to tens of microseconds before the application of voltage would significantly reduce both delay and jitter to discharge initiation. Higher laser energy applied after voltage rise is observed to cause gas breakdown in under 100 ns