Recycling and neutral transport in the DIII-D Tokamak

Conference · Fri Apr 01 04:00:00 EST 1988

OSTI ID:6889539

Allen, S L; Rensink, M E; Hill, D N; Perkins, D E; Jackson, G L; Mahdavi, M A

Several diagnostics have been used to characterize the edge plasma in the DIII-D divertor region and thereby to understand the particle recycling and neutral particle transport in an open divertor. An array of Langmuir probed mounted on the carbon divertor plates determines that generally the electron temperature is low (T/sub e/ approx. = 10-20 eV), and the electron density is high (n/sub e/ approx. = 5 /times/ 10/sup 19/ m/sup /minus 3//). The edge plasma temperature and density are also measured by a movable Langmuir probe mounted at the midplane of the plasma; the data from these shot-by-shot edge radial scans are then connected with the data for the core plasma obtained by Thomson scattering. The heat flux to the divertor plates is measured by an absolutely calibrated infrared camera; a plasma model is used to compare the heat flux with the measured T/sub e/ and n/sub e/. The molecular neutral pressure at the edge of the plasma at several poloidal and toroidal locations is obtained from absolutely-calibrated pressure gauges; a gas puff enables in-situ gauge calibrations before each plasma shot. Typically, the divertor pressure is 10-50 times larger than that at the midplane. Time-resolved H/sub ..cap alpha../ brightness measurements are obtained from an absolutely calibrated television camera viewing the divertor region from above; both strike points are viewed simultaneously. The emission from the inner and outer strike points are usually equal after the H-mode transition, but are often unequal after the first ELM in H-mode and during some phases of L-mode discharges. A tangential camera measures the falloff in emission from the X-point to the plasma midplane. 26 refs., 8 figs., 1 tab.

• Research Organization: General Atomics Co., San Diego, CA (USA)
• DOE Contract Number: AC03-84ER51044
• OSTI ID: 6889539
• Report Number(s): GA-A-19292; CONF-880512-7; ON: DE88012428
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
700103 -- Fusion Energy-- Plasma Research-- Kinetics
CLOSED PLASMA DEVICES
DIVERTORS
DOUBLET-3 DEVICE
ELECTRIC PROBES
ELECTRON DENSITY
ELECTRON TEMPERATURE
HEAT FLUX
INELASTIC SCATTERING
LANGMUIR PROBE
NEUTRAL-PARTICLE TRANSPORT
PLASMA DIAGNOSTICS
PLASMA SIMULATION
PROBES
RADIATION TRANSPORT
SCATTERING
SIMULATION
THERMONUCLEAR DEVICES
THOMSON SCATTERING
TOKAMAK DEVICES