Temporal response of a surface flashover on a velvet cathode in a relativistic diode

Surface flashover of a carbon fiber velvet cathode generates a discharge from which electrons are relativistically accelerated to c ranging from 4.9 to 8.8 through a 17.8 cm diode. This discharge is assumed to be a hydrocarbon mixture. The principal objective of these experiments is to quantify the dynamics over the similar to 100 ns pulse of the plasma discharge generated on the surface of the velvet cathode and across the anode-cathode (A-K) gap. A qualitative comparison of calculated and measured results is presented, which includes time resolved measurements with a photomultiplier tube and charge-coupled device images. In addition, initial visible spectroscopy measurements will also be presented confirming the ion species are dominated by hydrogen. (C) 2015 AIP Publishing LLC.