Experimental investigation of electron emission of a tungsten cathode in a cesium plasma

The voltage drop at a tungsten cathode surrounded by cesium plasma is measured as a function of the current density and temperature of the cathode. Current densities, an order of magnitude higher than predicted by the Langmuir S curves, accompanied with low voltage drops, have been measured for certain cathode temperature regimes. These results seem to be of interest for the emission properties of electrodes in closed-cycle MHD generators.