Absolute Electron Density Measurements in Turbulent Hypersonic Sphere Wakes with Langmuir Probes
DEFENCE RESEARCH ESTABLISHMENT VALCARTIER (QUEBEC)
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Measurements were carried out in the ballistic range facilities at DREV of the absolute electron density levels in the wakes of 2.7 inch diameter spheres flown at 14,500 feetsecond in air atmospheres at 10 torr. The experimental technique involved the use of Langmuir probes, following the theoretical demonstration of feasibility of such an experiment by G.W. Sutton. Considerable attention was paid to details of the experiment, such as probe cleanliness, minimum flow disturbance and the minimization of reflected shocks. Electron density level estimates obtained with the Langmuir probes were in good agreement with those estimates derived from simultaneous measurements with a microwave interferometer. The behavior of the plasma potential in the wake was also determined the plasma potential apparently attempted to maintain itself close to the potential of the most highly biased probes, but the reason for this behavior has not been established.
- Test Facilities, Equipment and Methods
- Fluid Mechanics
- Plasma Physics and Magnetohydrodynamics