Heat Balance in the Positive Column of a Glow Discharge

Abstract

According to classical concepts, a cylindrical positive column (PC) of the glow discharge (GD) is a luminous volume of ionized gas that fills up the whole space in the discharge chamber (DC) and which parameters are indiscrete, i.e. they do not vary along the axis of the chamber. In this case, the heat balance of the PC is that the electric power released in the discharge is expended on the heat flux to the wall of the discharge chamber (DC) due to heat transfer; also, a certain fraction of energy is carried away due to heat transfer by radiation. In case of an open system when gas flows through the area of the PC, it is possible to change the discharge parameters along its axis, and it is necessary to take into account heat transfer by convection in the energy balance. It is important to have knowledge of heat balance and its components both for gas discharge physics and for any DC designed for various applications. This paper is devoted to a comprehensive experimental study of the distribution of potential, electric field intensity, and gas temperature in the longitudinal GD. The gas pressure P, its flow rate G, the discharge current I and its voltage U varied accordingly in the following ranges: P = (2 – 9) kPa, G = (0 – 0.05) g/s, I = (30 – 80) mA, U= (1 – 2) kV. The obtained distribution of potential, electric field intensity, and gas temperature make it possible to calculate all the heat fluxes in the plasma of the discharge PC.