Determination of the Pressure and Temperature of the Radiating Arc Plasma from the Measured Photocurrent, Voltage and Discharge Current Values

Abstract

It is shown that the pressure and temperature of the radiating arc plasma can be determined from the measured values of the voltage on the plasma column, the discharge current and the photocurrent caused by the radiation flux of the entire volume of plasma to the photodetector. For the case of axially symmetric homogeneous arc plasma in a state of the local thermodynamic equilibrium, equations are formulated that connect the plasma parameters with the measurement results. The equation for the photocurrent is obtained from the solution of the radiation transfer equation in the arc plasma of the arbitrary optical density. The cases of electrode surfaces reflecting and absorbing electromagnetic radiation are considered. It is shown that the problem of determining the parameters of the arc plasma is reduced to solving a system of two non-linear equations with respect to pressure and temperature. The described method is used to determine plasma parameters of a high-current vacuum arc at the stage of the anode activity. The stability of the method with respect to the errors of the initial data is shown by the example of the vacuum arc plasma.