Spectroscopic observations of UV-laser-induced flashover across an angled insulator

Temporally resolved visible-light spectra of the emission from the plasma formed by the ultraviolet-laser-induced flashover of an angled polymeric insulator have been measured. Because the insulator and each of the electrodes are of different materials, the source of the constituents of the plasma can be identified. The temporal evolution of the flashover event can be inferred by correlating the spectroscopic evidence with postshot damage patterns found on the electrodes and with previous open-shutter photographs of the discharge. These data are consistent with previously proposed surface flashover mechanisms