The influence of a solid spacer on the temporal development of laser initiated prebreakdown current in air at atmospheric pressure

The temporal development of prebreakdown currents in uniform field air gaps (around 1cm. length) is investigated. These gap currents were determined by observation of changes in potential across a resistor in series with the gap. While in previous work avalanche initiating electrons were released mainly through the use of spark gap radiation, here a short duration nitrogen laser pulse released electrons from the cathode. Although a detailed explanation is premature, a previously unreported after current was observed in the presence of a Teflon spacer. Since the air gap by itself behaved as observed by other authors using similar techniques, it appears that a valid new observation has been made.