Temperature Rise and Radial Profiles in CO2 Lasers

An analytical model is presented which provides results for the radial distribution in gas temperature, electron density, and current density in conventional electric-discharge CO2–N2–He lasers. The heat-conduction and electron-diffusion equations are solved, and it is shown that (i) the radial electron density distribution differs only slightly from the usual Bessel-function profile for centerline gas temperature up to 600 °K and (ii) the laser gas-temperature profile is essentially independent of pressure and depends only on the total power input per unit length of tube. Calculated centerline-to-wall temperature differences are in good agreement with experiment, falling about 5% above measured values.