Influence of electron beam generation on the parameters and emission characteristics of a constricted arc discharge in a pulsed forevacuum plasma-cathode electron source

Abstract

We have explored the influence of accelerating voltage, gas pressure, and accelerating gap length on the discharge parameters and emission characteristics of the plasma of a constricted arc discharge which forms the emission plasma in a forevacuum-pressure, plasma-cathode, broad-beam electron source. We find that the back-streaming ion flux from beam plasma, formed by electron beam in the accelerating gap and beam propagation region, leads to increase in the maximum current and pulse duration of the constricted arc. The rise-time of the emission current pulse (and electron beam current pulse) depends not only on the formation of the emission plasma but also on changes in arc current flow conditions in the constricting channel, which occur during the pulse duration due to the back-streaming ion flux. There is a significant influence of accelerating gap length on the emission characteristics. Varying the accelerating gap length provides control of the delay time and rise time of the emission current pulse (e-beam current pulse), as well as the electron emission efficiency.