Calculation of Parameters of Positive Column in Laser Tubes of Variable Diameter

Abstract

Processes in the positive column of a direct current discharge in a gas in laser tubes of variable diameter have been considered. A system of equations is obtained that relates internal characteristics of the positive column (concentration of charged particles, electron temperature, and longitudinal electric field strength) to the external parameters of the column (varying radius of the discharge channel, gas inlet pressure and discharge current). These equations are derived from fairly general assumptions about gas in a laser. The charged particles motion equations, the charged particle balance equations and the electrons energy balance equation were used to obtain this system. This system of equations solves the problem. Numerical calculations were carried out and the internal characteristics of the positive column were calculated as a function of the axial distance along the tube at typical values of the external parameters of the column.