ALT-I pump limiter experiments

Technical Report · Tue Sep 01 00:00:00 EDT 1987

DOI:https://doi.org/10.2172/5929099· OSTI ID:5929099

Goebel, D M; Conn, R W; Campbell, G A; Leung, W K; Dippel, K H; Finken, K H; Wolf, G H; Thomas, G J; Pontau, A E; Hsu, W

Results from the ALT-I pump limiter experiments in TEXTOR are presented. ALT-I has demonstrated control of the plasma density in a high recycling tokamak by pumping up to 15% of the core efflux. The closed pump limiter designs with restricted entrance geometries to reduce the backflow of neutral gas to the plasma remove over 50% of the ion flux incident on the collection slot. Up to 80% of the entrance ion flux is removed when the edge electron temperature is less than 10 eV and plasma-neutral gas interactions are minimized inside the limiter. Results from a 3-D Monte Carlo neutral gas transport code agree closely with these experimental results. The compound curvature of the head is found to distribute the heat over the surface as predicted in the original designs. Impurity removal experiments demonstrate that significant helium exhaust can be achieved with a pump limiter. During ohmic heating in TEXTOR, the energy and particle confinement times are proportional to the line averaged core density. With ICRH auxiliary heating, tau/sub E/ follow L-mode scaling independent of particle removal by the pump limiter. Pump limiter operation does not directly modify the SOL plasma density and electron temperature, but controls the core plasma density by changing the global recycling at the boundary. The global particle confinement, the particle flux to the limiter, and the edge electron temperature follow the changes in the core density and auxiliary heating power. 25 refs.

• Research Organization: California Univ., Los Angeles (USA). Dept. of Mechanical, Aerospace and Nuclear Engineering; Association Euratom-Kernforschungsanlage Juelich (Germany, F.R.). Inst. fuer Plasmaphysik; Sandia National Labs., Livermore, CA (USA)
• DOE Contract Number: FG03-85ER51069
• OSTI ID: 5929099
• Report Number(s): UCLA/PPG-1084; ON: DE88000822
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101 -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
700209* -- Fusion Power Plant Technology-- Component Development & Materials Testing
BOUNDARY LAYERS
CLOSED PLASMA DEVICES
CONFINEMENT
CONFINEMENT TIME
CURRENT-DRIVE HEATING
EFFICIENCY
ELECTRIC HEATING
ELECTRON TEMPERATURE
HEAT FLUX
HEATING
HIGH-FREQUENCY HEATING
ICR HEATING
INELASTIC SCATTERING
JOULE HEATING
LAYERS
LIMITERS
MONTE CARLO METHOD
PERFORMANCE TESTING
PLASMA CONFINEMENT
PLASMA DENSITY
PLASMA HEATING
PLASMA SCRAPE-OFF LAYER
POWER DENSITY
PUMPED LIMITERS
RESISTANCE HEATING
SCATTERING
TEMPERATURE DEPENDENCE
TESTING
TEXTOR TOKAMAK
THERMONUCLEAR DEVICES
THOMSON SCATTERING
TOKAMAK DEVICES
WALL LOADING