Parameters of a Longitudinal DC Discharge in a Supersonic Air Flow

This work is devoted to the study of the properties of a discharge in a supersonic air flow and the problem of determining the temperature of a contracted (thin cylindrical) plasma channel with a radial temperature distribution. The paper considers a direct discharge 30 mm long far from the channel walls in the core of a supersonic flow with the following parameters: Mach number M = 2, flow rate V similar to 500 m/s, stagnation temperature T-0 = 300 K, and static gas pressure P-st = 22 kPa. The axisymmetric geometry of the ex-periments with two coaxial electrodes located parallel to the flow was chosen to avoid the appearance of a part of the current channel perpendicular to the flow and the corresponding discharge pulsations. The current-voltage characteristic was obtained, and the dependences of the temperature of the electric discharge plasma on the electrical parameters of the discharge were obtained using emission spectroscopy. Also, with the help of shadow visualization and high-speed shooting, an estimate was obtained of the thickness of the thermal cone and the discharge channel and their dependence on the discharge current.