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

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.