Effect of shock wave propagation on plasma emission in a low pressure N/sub 2/ discharge

The interaction between Mach 1.7 acoustic shock waves with 5 torr, 2.5 mA/cm/sup 2/ current density glow discharges in nitrogen was quantified from current-voltage behavior and time resolved two-dimensional C-B plasma emission. These measurements are consistent with the formation of localized electric double layer sheaths traveling with the propagating shock wave. This space-charge layer provides local enhanced ionization at the shock front which permits maintenance of the discharge current continuity, at least during the short shock propagation time, when the decrease in E/N, (E-electric field and N-gas density) behind the shock produces a dark discharge spanning the entire 30-cm column length.