MEASUREMENT OF THE RADIAL METAL VAPOR DISTRIBUTION IN A PSEUDOSPARK SWITCH

Radial density profiles of molybdenum vapour in the centre of the elec trode gap of a pseudospark switch have been obtained using one-dimensi onal laser-induced fluorescence imaging. Owing to the random nature of generation and motion of electron emission sites, which are the predo minant metal vapour sources, the vapour density distribution fluctuate s strongly from one discharge to another. However, from the positions of the maxima of the distribution it can be inferred that emission sit es occur primarily on the edges of the cathode hole. Although the abso lute number density of Mo vapour emanating from cathodes containing ta ntalum carbide increases with the tantalum carbide concentration, no m arked differences in shape and temporal development of the density pro files can be identified.