Spectroscopic study of edge poloidal rotation and radial electric fields in the DIII-D tokamak

Conference · Mon Oct 01 04:00:00 EDT 1990

OSTI ID:6503693

Groebner, R J; Burrell, K H; Gohil, P; Seraydarian, R P

Doppler-shift spectroscopy has shown that finite values of poloidal rotation velocity {upsilon}{sub {theta}} and of radial electric field E{sub r} exist at the edge of a tokamak plasma and that dramatic increases occur in these parameters at an L-H transition. E{sub r} is negative in the L-mode and becomes more negative in the H-mode; {upsilon}{sub {theta}} increases in magnitude at the transition. In addition, the radial gradients (shear) of {upsilon}{sub {theta}} and E{sub r} are large and these gradients also increase at the L-H transition. These results are based on measurements of Doppler shifts of light emitted by He II ions, located in a region about 1--3 cm inside the separatrix. These observations have been made with horizontally-viewing and vertically-viewing spectrometer systems on the DIII-D tokamak. The nearly orthogonal views of these systems are used to determine the plasma's flow velocity in terms of the orthogonal sets {upsilon}{sub {theta}} and {upsilon}{sub {phi}} or of {upsilon}{sub {perpendicular}} and {upsilon}{sub {parallel}}. Knowledge of {upsilon}{sub {perpendicular}} is used to calculate E{sub r} from the force balance equation for a single ion species. The existing results impose constraints on theories of the L-H transition. More detailed studies of the spatial profiles and temporal evolution of {upsilon}{sub {theta}} and E{sub r} will be made with upgraded instrumentation, which is now coming on-line. 28 refs.

• Research Organization: General Atomics, San Diego, CA (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC03-89ER51114
• OSTI ID: 6503693
• Report Number(s): GA-A-20100; CONF-900557--28; ON: DE91002706
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
BOUNDARY LAYERS
CONFINEMENT
DOPPLER EFFECT
DOUBLET REACTORS
ELECTRIC FIELDS
ELECTRON DENSITY
ELECTRON TEMPERATURE
EMISSION SPECTROSCOPY
H-MODE PLASMA CONFINEMENT
LAYERS
MAGNETIC FIELDS
PLASMA
PLASMA CONFINEMENT
PLASMA DIAGNOSTICS
PLASMA SCRAPE-OFF LAYER
ROTATING PLASMA
SPECTROSCOPY
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS