Magnetic- and material-limiter discharges in Tokapole II

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5537219

Moyer, R A

Disruptive instabilities were studied in Tokapole II, a small poloidal-divertor tokamak, in magnetic- and material-limiter configurations. In the magnetic limiter configuration, the divertor separatrix defines the tokamak current channel boundary. Limiters or neutralizer plate are not used to remove plasma in the scrape-off region. The relatively hot, dense plasma in the scrape-off region carries 5-20% of the current. In the material-limiter configuration, limiter plates are inserted to the separatrix to remove plasma and current in the scrape-off region. The plates vary the tokamak current-channel boundary condition in a controlled manner, and provide a benchmark for comparison with other tokamaks. Internal and external disruptions have been studied, and several unique features in the magnetic-limiter configuration were identified. The magnetic-limiter configuration enables routine passing of the stability barriers at q(a) = 2 and q(a) = 1, where q(a) is the edge safety factor, without a close-fitting wall, external windings, or detailed profile control techniques. Passing the q(a) = 1 barrier permits operation in the q < 1 regime where total reconnection of the sawtooth does not occur.

• Research Organization: Wisconsin Univ., Madison, WI (USA)
• OSTI ID: 5537219
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
BOUNDARY CONDITIONS
BOUNDARY LAYERS
CLOSED PLASMA DEVICES
DIVERTORS
INSTABILITY
INTERNAL RING DEVICES
LAYERS
PLASMA INSTABILITY
PLASMA SCRAPE-OFF LAYER
POLOIDAL FIELD DIVERTORS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TOKAPOLE DEVICES