Unified Analytical Treatment Of Near- Cathode Layers Of Arc Discharges With Application To Spotless Cathodic Attachment Of Vacuum Arcs

Under typical conditions of arc discharges, both in vacuum and ambient gases, a significant electrical power is deposited by the arc power supply into a thin near-cathode plasma layer, comprising the space-charge sheath and eventually the adjacent ionization layer. It is in this layer that the ion flux to the cathode surface is generated. A part of the deposited power is transported by the ion flux to the cathode surface, thus heating it to temperatures sufficient for electron emission, and the rest is transported into the bulk plasma. The aim of this work is to revisit the available formulas, to modify them where appropriate, and to present in a s ready-for-use form in the whole range of conditions of practical interest. As an example, the formulas are applied to analysis of spotless cathode attachments of vacuum arcs. Calculation results are reported for lead and chromium cathodes. Also given, for the purpose of comparison, are results for gadolinium cathodes.