An electrochemical approach to the interfaces in metal-vacuum-metal arcs: Comparison and contrast with the metal-electrolyte-metal situation

A novel conceptual approach treating metal-vacuum-metal sandwiches in the arc regime as electrolysis cells is presented. A qualitative comparison and contrast between the fundamental features of the two devices is carried out. The cathode fall region of the arc is shown to be a type of “double” layer region as for the ordinary metal-electrolyte interface. A schematic description of the metal-plasma interphasic region (i.e, the cathode fall) is given in electrochemical terms. The concepts provide an electrochemical model for the quantitative calculation of the magnitudes of the electrode potentials appropriate to the metal-plasma interfaces obtaining at the cathodes of arcs. It is pointed out that the agreement between the experimental cathode fall values and those calculated on the basic of the electrochemical model previously by us is excellent for thirty-two metals for which reliable experimental V_c values are available in the literature.