VELOCITY-MEASUREMENT IN HYPERSONIC FLOWS USING ELECTRON-BEAM-ASSISTEDGLOW-DISCHARGE

A new pseudospark-type electron gun has been utilized in the F4 high-e nthalpy, low-density, hot-shot wind tunnel at ONERA. The main goal was to perform accurate measurements of the velocity profile across the b oundary layer and the freestream through a time-of-flight principle. I n these experiments, an intense pulsed electron beam traces the path o f a high-voltage, sustained-glow discharge in some 10 ns. A charge-cou pled device camera is opened briefly, 5 mu s after the electron gun ac tuation, to image the position of the luminous column convected by the flow.