Potential Distributions in a Low-Pressure Thermionic Converter

Abstract

A plane diode model of a low-pressure cesium-filled thermionic converter is treated. It is assumed that all ions and electrons are created at the surface of the hot cathode with a Maxwellian distribution corresponding to the cathode temperature. The charged species are then assumed to move through the plasma, consisting of electrons, ions, and neutral cesium atoms, as free particles under the influence of their mutual space charge field. A method is outlined by which the potential distributions corresponding to different operating conditions may be calculated completely. In this fashion the operating characteristics of the converter may be related to the self-consistent space charge potentials. Instabilities as possible sources of tube oscillations are briefly discussed.