Chemical instabilities in the XeCl laser discharge: a stochastic approach

A simple stochastic model for the electron kinetics in Ne/Xe/HCl discharges for XeCl lasers is proposed in order to investigate the non-equilibrium fluctuations of the electron density. Critical fluctuations are observed for a discharge which is controlled by electron attachment to molecules, but not for a recombination-controlled discharge. A connection is proposed between this mechanism and the observed rapid spoiling of the optical quality of the XeCl laser plasma on increasing the HCl mole fraction in the discharge mixture.