Thermoelectric Properties of the Plasma Diode

Abstract

The thermoelectric properties of a gas-filled diode containing a high density of positive ions are discussed in some detail. The complete circuit of diode and load is treated as a thermocouple, and expressions for both the Seebeck emf and thermoelectric conversion efficiency are obtained as a function of cathode and anode temperatures. The interior of the diode is divided, for convenience, into three regions: (1) the cathode sheath, (2) main body of plasma, and (3) the anode sheath. The anode sheath is the region of large temperature gradient; the approximate temperature distribution in the sheath is obtained by solving a greatly simplified heat-conduction equation. Finally, the results of this analysis are compared with experiments performed by Grover, Roehling, Salmi, and Pidd.