Development and application of the electron beam fluorescence technique for visualizing hypersonic high temperature airflows

The electron beam fluorescence technique has been employed for visualizing hypersonic airflows. A high current electron beam generator was used to provide electron beams with currents up to 20 ma at voltages up to 40 kV. Applications of the technique at low densities illustrate that many details of the flow field can be obtained in density regions where conventional optical systems fail to yield useful results. The value and versatility of the method is demonstrated by results obtained with a sharp cone model and advanced ramjet aircraft configuration in a Mach 10 airflow. Techniques for obtaining quantitative density measurements with photographic and/or photomultiplier techniques are discussed.