Self-sustained self-sputtering: a possible mechanism for the superdense glow phase of a pseudospark

Self-sustained self-sputtering occurring during high current pseudospark operation (/spl ap/10/sup 4/ A/cm/sup 2/, I>10/sup 3/ A) is shown to be a possible mechanism for the superdense glow. The mean-free-path for ionization of cathode material sputtered in the low-current hollow-cathode phase can be shorter than the cathode-anode gap distance, and ionized atoms can return to the cathode surface, self-sputtering with a yield greater than one. The self-sputtered cathode atoms become ionized in the beam of electrons accelerated in the cathode sheath. A large fraction of the discharge current at the cathode surface can be carried uniformly over the surface by ions and a very high electron emission density is not required to maintain the high current.>