Experiments conducted in a new, small-scale, nonequilibrium plasma wind tunnel recently developed at Ohio State University are discussed. The facility provides a steady-state supersonic ow of cold nonequilibrium plasma with well-characterized, near uniform, properties. The plasma is produced in aerodynamically stabilized highpressure glow discharge that forms the plenum of the supersonic nozzle. The possible modi cation of the supersonic ow due to ionization is studied by measuring the angle of oblique shocks attached to the wedge located in the nozzle test section. The results do not show any detectable shock weakening or attenuation in weakly ionized nitrogen plasma, compared to the measurements in a nonionized gas ow. Experiments in supersonic owing nitrogen and helium afterglow also demonstrate a novel technique for high-density supersonic ow visualization. It allows identifying all key features of the supersonic ow, including shocks, boundary layers, ow separation regions, and wakes by recording intense visible radiation of the weakly ionized plasmas. Interpretation of radiation intensity distributions in nonequilibriumsupersonic owing afterglow may provide information on key mechanisms of energy storage and ultraviolet radiation in high-altitude rocket plumes. In addition, these ow visualization experiments can be used for validation of multidimensional computer ow codes used for internal ow simulation.

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