Unipolar arcs in nuclear fusion devices: An example of a wear phenomenon

Although 'wear' phenomena are well-known in bipolar arcs (e.g. electrode consumption during the arc processes), such phenomena have not been previously pointed out for unipolar arcs in the literature on the wear of surfaces. It is clear from Fig. 1 here that the metal vapour and ions can be ejected into the plasma from the cathode spots on the metal, thus leading to wear of the latter. (orig./HKN)