Self-sustained volume discharge in SF6-based gas mixtures upon the development of shock-wave perturbations of the medium initiated by a pulsed CO2 laser

Abstract

A self-sustained volume discharge in SF6 mixtures with C2H6, He, and Ne preliminarily irradiated by CO2 laser pulses was investigated. The radiation energy density absorbed by SF6 in the discharge ignition region amounted to 6.5 J atm-1 cm-3. The discharge structure and the current distribution in the discharge gap were found to change radically with increasing the time delay between the laser and discharge pulses. In particular, brightly glowing narrow channels are formed at the boundary of the irradiation region. The observed effect is shown to arise from the development of a shock-wave process due to a temperature jump at the boundary between the irradiated and unirradiated gas. The velocities of shock wave propagation and the main thermodynamic gas parameters in the perturbation region were calculated. A comparison was made between the calculated and measured velocities of the shock waves.