Collective ion acceleration in spark stage of vacuum discharge

Mechanism of the collective acceleration of anomalous ions at the spark stage of a vacuum discharge is proposed. 2D electromagnetic particle-in-cell code was developed to study the mechanism. Computer simulation showed that ions are accelerated in the presence of a plasma cloud in the interelectrode gap, where the development of strong electron instability during the propagation of a cathode electron beam leads to potential buildup to a level exceeding the applied voltage. The appearance of accelerated ions of the interelectrode plasma is accompanied by a jump in the diode current.