Estimating cathodic plasma jet parameters from the vacuum arc charge state distribution

An analysis of the ion charge distribution measurements in a vacuum arc plasma has been carried out. It has been demonstrated that, by using the Saha equation, one can determine the electron temperature T e and density N e in the cathode spot plasma. It has also been shown that it is possible to estimate a microspot diameter d and a current density j in the microspot by applying a theoretical model. The values obtained for T e approximately=4-10 eV, N e approximately=10 26 -10 28 m -3 , d approximately=0.2-0.5 mu m and j approximately=(1-30)*10 12 A m -2 are in agreement with recent measurements.