Electron Beam Technique: A Review for Wind Tunnel Application

Abstract

A description of the principles and problems arising with electron beam application in rarefied gas dynamics is given. The electron beam technique can provide measurements of gas density, temperatures (rotational and vibrational), and velocity in several gas species. In this paper temperature measurement of nitrogen is reviewed. In addition the ion tracing method is introduced; the flow velocity is substantially derived from a time-of-flight measurement of ions, produced by a short-pulsed high energy electron beam. Several examples of electron beam application to supersonic wind tunnels are demonstrated. Finally the twodimensional flow visualization is discussed.