Electron-beam generation during the hollow cathode phase of pseudospark discharges

From calculations using a two-dimensional, hybrid fluid-particle model, the mechanism for the production of the high-current electron beam observed during the hollow cathode phase of pseudospark discharges is identified. The predicted beam properties are in good qualitative agreement with experiments; the onset of the beam current is abrupt and the current in the beam is some 10%–30% of the discharge current. Two distinct components appear in the energy spectrum of the beam. A sizable fraction of the current is carried by electrons with an energy corresponding to the voltage applied to the discharge. A distinct low-energy beam is also predicted with a spread in energy of several 100s of eV.