Plasma spikes for the mitigation of shock waves

Summary form only given, as follows. Plasma spikes for the reduction of sonic boom and wave drag in supersonic flights are being developed. Experiments have been conducted in a Mach 2.5 wind tunnel. A cone-shaped model having a 600-cone angle was used as the shock wave generator, which resembled a supersonic vehicle. The tip and the body of the model were designed as two electrodes with the tip of the model designated as the cathode for gaseous discharges, which produced a plasma in the nose region of the model where shock waves were formed in a supersonic flow. The produced plasma acted as a spatially distributed spike, which interacts with the incoming flow prior to the wind-tunnel model. The effect of this plasma spike on the shock wave formation was explored by shadowgraphs and Schlieren images of the flow field taken during a wind tunnel run. Two types of discharges, 60 Hz self-sustained diffused arc discharge and a pulsed dc discharge, have been applied for on-board plasma generation.