DIAGNOSTIC STUDIES IN AN INDUCTION-HEATED SUPERSONIC ARGON PLASMA.
CALIFORNIA UNIV BERKELEY COLL OF ENGINEERING
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Diagnostic studies were carried out in an induction-heated low density supersonic plasma jet. The neutral number of densities were obtained from the calibrated intensity of the 4609A line of argon excited by a 25 kilovolt electron beam. The contribution to the 4609A line due to the plasma self-emission was found to be negligible. The velocities and heavy particle temperatures were determined by measuring the Doppler shift and Doppler-broadening of the 4609A line with a Fabry-Perot interferometer in two linearly independent directions, following a technique developed by Muntz. The density, impact pressure, and velocity along the free jet centerline all followed the isentropic source flow model up to the Mach disc. The temperature, however, showed an unexpected rise above the isentropic prediction. Ion number densities and electron temperatures were measured with a double Langmuir probe. The fraction of ionization was frozen at about 0.1 along the free jet axis. Calculations are made of the fraction of the energy of recombination absorbed by the electrons and the fraction lost by radiation. Author
- Plasma Physics and Magnetohydrodynamics