The Regimes for Sustaining a Hollow-Cathode Glow Discharge with a Hot Filament Inside the Cavity

The results of investigations of a low-pressure hollow-cathode glow discharge with a hot filament (thermionic cathode) inside the cavity are presented. The current-voltage characteristics (CVCs) of the discharge and the dependences of the current delivered to the thermionic and hollow cathodes on the discharge burning voltage are obtained at different gas pressures and filament currents. It is shown that the major fraction of the current is transferred in the thermionic cathode circuit. For interpretation of the CVCs, a model is accepted, which uses a generalized coefficient (rather than a conventionally utilized secondary-emission coefficient), which includes not only the cathode bombardment with ions but also the emission current induced by an external source. An estimation is made of the discharge parameters. The model is shown to be quite consistent with the experiment.