Optical diagnostics of switching vacuum arcs

Optical diagnostic methods, which can be used for determination of arc plasma temperature, anode surface temperature, densities of plasma species during the arcing and in the post-arc phase are presented. Those methods have been applied for determination of the properties of high-current vacuum arcs in dependency on the anode activity (various highcurrent anode modes). A model vacuum circuit breaker was used to grant the optical access to the arc plasma and to the electrodes. Typical switching conditions, i.e. arc initialization by separation of CuCr contacts during the AC operation in the range 1-28kA magnitude have been used. The methods are exemplarily illustrated with corresponding results.