THEORETICAL AND EXPERIMENTAL INVESTIGATION OF ARC PLASMA-GENERATION TECHNOLOGY. PART 2: APPLIED RESEARCH ON ELECTRIC ARC PHENOMENA. VOL. 1: A THEORETICAL AND EXPERIMENTAL STUDY OF THERMIONIC ARC CATHODES
Final rept. 1 Aug 1960-30 Nov 1962
AVCO CORP WILMINGTON MA RESEARCH AND ADVANCED DEVELOPMENT DIV
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The operating mechanism of thermionic arc cathodes is studied theoretically and experimentally. A theoretical model is formulated including important processes in the plasma of the cathode fall zone, at the plasma cathode interface, and in the cathode interior. In principle, this model permits detailed calculations of cathode performance solely from geometrical considerations and the physical properties of the cathode material and the gas. An approximate analysis indicates that the system has two different types of solution, the occurrence of which depends primarily upon how well the cathode is cooled. Well cooled cathodes tend to operate with a concentrated arc spot, while very poorly cooled cathodes operate without such a spot. Approximate solutions are worked out in numerical detail for spot-mode operation of a semi-infinite cathode and spotless mode operation of a thin rod shaped cathode cooled at one end. The results of a series of experiments on rod shaped thoriated tungsten cathodes are reported. The theory correctly predicts general trends of these data.
- Plasma Physics and Magnetohydrodynamics