Characteristics of a Plasma Thermocouple

Abstract

The operation of a cesium plasma thermocouple is described for a range of hot-junction temperatures from 1600°K to 2600°K and for a range of cesium pressures from 10−5 mm Hg to 2 mm Hg. Electromotive force and short-circuit current data are presented for cells containing three different emitter substances: Ta, ZrC, and (ZrC) (UC). In the range of pressure and temperature variation studied, the observed electromotive forces are between 1 and 4.5 volts. Short-circuit current depends markedly on the current emission properties of the hot electrode. The largest short-circuit current density observed for the (ZrC) (UC) emitter, is 62 amperes per square centimeter.