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U.S. Department of Energy
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ENHANCED INTERACTION IN THE POSITIVE COLUMN

Technical Report ·
DOI:https://doi.org/10.2172/4184276· OSTI ID:4184276
Recent theoretical work has shown that under certain conditions enhanced interaction may be present in a plasma. The influence of such enhanced interaction on the characteristics of the positive column in a longitudinal magnetic field is investigated. The calculations are based on the Boltzmann transport equations, using an effective interaction parameter. From the law of momentum conservation it appears that enhanced interaction causes enhanced diffusion by counteracting the influence of the magnetic field. Related to this is a pronounced influence on the radial potential distribution in the discharge. Both effects depend on the type of diffusion, showing characteristic differences between pure ambipolar diffusion, Simon diffusion, and intermediate types of diffusion. The law of particle conservation, which defines the electron temperature (T-) in the discharge, is only indirectly--via the diffusion coefficient-- influenced by enhanced interaction. This influence on the electron temperature is in general small. In particular it is shown that nonuniform enhancement may not affect T/sub -/ at all. The law of energy conservation yields, for a given electron temperature, an increase in the ion (T/sub +/) and gas (T/sub 0/) temperatures, and with that an increase in T/sub +//T/sub -/. More important, it shows that the relation X/sub z/(T/sub -/) between the electron temperatare and the longitudinal electric field (X/sub z/) is strongly affected by enhanced interaction. Utilization of these results suggests a new method to investigate experimentally the presence of enhanced interaction in the discharge. This method is based essentially on the measurement of the radial potential distribution. (auth)
Research Organization:
California Univ., Berkeley, CA (US). Lawrence Radiation Lab.
Sponsoring Organization:
US Atomic Energy Commission (AEC)
DOE Contract Number:
W-7405-ENG-48
NSA Number:
NSA-14-018521
OSTI ID:
4184276
Report Number(s):
UCRL-9144
Country of Publication:
United States
Language:
English