On the ion energy distribution of high current arcs in vacuum

This is the authors' abstract. We don't add key points for this paper.

With the experiments presented in this paper, applications of a retarding field analyzer (RFA) for the measurement of the ion energy E/sub i/ in a vacuum arc plasma are discussed. The examined plasma was produced by a sinusoidal half-wave vacuum arc current. The experiments were concentrated on evaluating the plasma parameters at the last three milliseconds before current zero. In a current range from 300 A/sub rms/ to 10 kA/sub rms/, the ion energy distributions and their peak values were evaluated. With the increase of the arc current, a decrease of the ion energy was found. By additional investigations of the angular distribution of the ion energies, a transition from a collision dominated interelectrode plasma to a freely expanding plasma was observed, depending on the arc current.