ELECTROTHERMALLY ACCELERATED PLASMA JETS.
Final technical rept., 1 Jun 65-31 May 66,
GIANNINI SCIENTIFIC CORP SANTA ANA CALIF
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Experimental and theoretical results are presented on the performance characteristics of the low pressure arc jet operated with hydrogen. Thermal and thrust power efficiency have been measured for up to 20 kilogauss applied magnetic fields and various electrode configurations and specific impulses. The thermal efficiency is insensitive to magnetic field strength and specific impulse in the high range of specific impulse. Thrust efficiency shows a dependence on the magnetic field for operating conditions which produce values of the Hall parameter much larger than unity, but this may be due to the much discussed spurious interactions of the arc with the environment. The efficiencies show a definite and fairly regular increase with increasing arc chamber pressure. Tests have been conducted which demonstrate qualitatively the effect of the applied field on the arc current distribution. A good two-parameter fit of thermal efficiency data is given, and an analytical model for the thermal losses is partially developed. Explicit expressions for the torque on the arc jet flow are obtained for two classes of idealized current distributions. An inequality is derived which places a lower bound on the torque for a given applied magnetic field and electrode configuration. Author
- Plasma Physics and Magnetohydrodynamics
- Electric and Ion Propulsion