Tokamak advanced pump limiter experiments and analysis

Conference · Wed Jun 01 04:00:00 EDT 1983

OSTI ID:6745200

Conn, R W

Experiments with pump limiter modules on several operating tokamaks establish such limiters as efficient collectors of particles and has demonstrated the importance of ballistic scattering as predicted theoretically. Plasma interaction with recycling neutral gas appears to become important as the plasma density increases and the effective ionization mean free path within the module decreases. In limiters with particle collection but without active internal pumping, the neutral gas pressure is found to vary nonlinearly with the edge plasma density at the highest densities studies. Both experiments and theory indicate that the energy spectrum of gas atoms in the pump ducting is non-thermal, consistent with the results of Monte Carlo neutral atom transport calculations. The distribution of plasma power over the front surface of such modules has been measured and appears to be consistent with the predictions of simple theory. Initial results from the latest experiment on the ISX-B tokamak with an actively pumped limiter module demonstrates that the core plasma density can be controlled with a pump limiter and that the scrape-off layer plasma can partially screen the core plasma from gas injection. The results from module pump limiter experiments and from the theory and design analysis of advanced pump limiters for reactors are used to suggest the major features of a definitive, axisymmetric, toroidal belt pump limiter experiment.

• Research Organization: California Univ., Los Angeles (USA)
• DOE Contract Number: AT03-80ER52062
• OSTI ID: 6745200
• Report Number(s): DOE/ER/52062-4; CONF-8309103-12; ON: DE84013579
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700209* -- Fusion Power Plant Technology-- Component Development & Materials Testing
BOUNDARY LAYERS
CLOSED PLASMA DEVICES
ENERGY SPECTRA
LAYERS
LIMITERS
PERFORMANCE
PLASMA DENSITY
PLASMA SCRAPE-OFF LAYER
RECYCLING
SPECTRA
THERMONUCLEAR DEVICES
TOKAMAK DEVICES