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Title: On the mechanism of operation of a cathode spot cell in a vacuum arc

The erosive structures formed on a tungsten cathode as a result of the motion of the cathode spot of a vacuum arc over the cathode surface have been examined. It has been found that the average mass of a cathode microprotrusion having the shape of a solidified jet is approximately equal to the mass of ions removed from the cathode within the lifetime of a cathode spot cell carrying a current of several amperes. The time of formation of a new liquid-metal jet under the action of the reactive force of the plasma ejected by the cathode spot is about 10 ns, which is comparable to the lifetime of a cell. The growth rate of a liquid-metal jet is ∼10{sup 4} cm/s. The geometric shape and size of a solidified jet are such that a new explosive emission center (spot cell) can be initiated within several nanoseconds during the interaction of the jet with the dense cathode plasma. This is the underlying mechanism of the self-sustained operation of a vacuum arc.
;  [1] ;  [2] ;  [3]
  1. P. N. Lebedev Physical Institute, RAS, 53 Leninsky Ave., Moscow 119991 (Russian Federation)
  2. Institute of Electrophysics, UB, RAS, 106 Amundsen St., Ekaterinburg 620016 (Russian Federation)
  3. A. M. Prokhorov General Physics Institute, RAS, 38 Vavilov St., Moscow 119991 (Russian Federation)
Publication Date:
OSTI Identifier:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 18; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States