Observation of Thermal Effects for Shock Wave Acceleration in Glow Discharge Plasma

Shock waves launched into weakly-ionized plasmas experiences an increased velocity and dispersion. These effects have been primarily attributed to: (i) gas temperature gradient and thermal effects, and (ii) plasma-specific (electron density, temperature, and electric field) effects. In this work, we investigate the thermal effects on the observed shock wave modifications in plasma. At a fixed Mach number, shock waves are launched with an incremental delay from the switch-on of the discharge. It is found that the shock wave velocity in plasma increases as the delay is increased, and reaches a steady-state value at a delay of about 100 ms.