The distribution of transit times in a magnetically steered cathodic arc

An electromagnetic system of coils capable of steering the cathode spot of a vacuum are has been implemented. The radius of the are track, and the velocity and confinement of the spot are controllable by suitable choice of coil currents. Measurements have been made on a range of cathode materials of the statistical distribution of the transit times of the orbiting spot. The measured distributions have been compared with predictions made from a stochastic model of steered are motion. Results are consistent with the model and with random are measurements of other authors.