CALIBRATION AND USE OF SPHERICAL AND CYLINDRICAL ELECTROSTATIC PROBES FOR HYPERSONIC WAKE STUDIES
AC ELECTRONICS-DEFENSE RESEARCH LABS SANTA BARBARA CA AEROSPACE OPERATIONS DEPT
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An experimental shock tube program was undertaken in order to calibrate electrostatic probes which may be used to make point ion density measurements in continuum flowing plasmas. An empirically derived formula which relates the ion density to the measured probe current was obtained in terms of the appropriate similarity parameters. This empirical correlation was used to interpret the ion currents collected by a radial array of negatively biased spherical probes which were positioned so as to intercept the ionized wake of a hypervelocity model in a ballistics range. The integrated ion densities were found to be in good accord with the integrated electron densities which were simultaneously measured using microwave methods. The application of the electrostatic probe measuring technique to the study of negative-ion chemistry in wakes is also illustrated and briefly discussed.
- Plasma Physics and Magnetohydrodynamics