V-I characteristics of pulsed CO2 laser discharges

Abstract

The voltage‐current dependence is investigated for pulsed self‐sustained uniform‐glow discharges by using commerical‐grade mixtures of CO₂, N₂, and He at near‐atmospheric pressures. For a given mixture, the discharge is found to stablize at a value of E/N which is independent of discharge current density, total pressure, and electrode spacing; E is the electric field and N is the number density of the gas. We interpret these observations as evidence that the glow condition is effectively controlled by attachment to CO₂ and also to H₂O, a gaseous impurity. Calculations of the E/N characteristic, based on a model which includes recombination and attachment losses, are in agreement with experimental results for all mixtures studied.