Particle removal with pump limiters in ISX-B

Conference · Sat Jan 01 04:00:00 EST 1983

OSTI ID:5496601

Mioduszewski, P; Emerson, L C; Simpkins, J E; Wootton, A J; Bush, C E; Carnevali, A; Dunlap, J L; Edmonds, P H; Gardner, W L; Howe, H C

First pump limiter experiments were performed on ISX-B. Two pump limiter modules were installed in the top and bottom of one toroidal sector of the tokamak. The modules consist of inertia cooled, TiC coated graphite heads and Zr-Al getter pumps each with a pumping speed of 1000 to 2000 l/s. The objective of the initial experiments was the demonstration of plasma particle control with pump limiters. The first set of experiments were performed in ohmic discharges (OH) in which the effect of the pump limiters on the plasma density was clearly demonstrated. In discharges characterized by: I/sub p/ = 110 kA, B/sub T/ = 15 kG, anti n/sub e/ = 1 - 5 x 10/sup 13/ cm/sup -3/ and t = 0.3 s the pressure rise in the pump limiters was typically 2 mTorr with the pumps off and 0.7 mTorr after activating the pumps. When the pumps were activated, the line-average plasma density decreased by up to a factor 2 at identical gas flow rates. The second set of measurements were performed in neutral beam heated discharges (NBI) with injected powers between 0.6 MW and 1.0 MW. Due to a cooling problem on one of the Zr-Al pumps the NBI experiments were carried out with one limiter only. The maximum pressure observed in NBI-discharges was 5 mTorr without activating the pumps, i.e., approximately twice as high as in OH-discharges. The exhaust efficiency, which is defined as the removed particle flux over the total particle flux in the scrape-off layer is estimated to be 5%.

• Research Organization: Oak Ridge National Lab., TN (USA); Tennessee Univ., Knoxville (USA); Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5496601
• Report Number(s): CONF-830795-6; ON: DE84003263
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700209* -- Fusion Power Plant Technology-- Component Development & Materials Testing
CARBIDES
CARBON COMPOUNDS
CHARGED PARTICLES
GETTERS
ISX TOKAMAK
LIMITERS
PERFORMANCE
REMOVAL
THERMONUCLEAR REACTORS
TITANIUM CARBIDES
TITANIUM COMPOUNDS
TOKAMAK TYPE REACTORS
TRANSITION ELEMENT COMPOUNDS
VACUUM SYSTEMS