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

Journal Article · Mon Oct 01 04:00:00 EDT 1990 · Review of Scientific Instruments; (USA)

DOI:https://doi.org/10.1063/1.1141777· OSTI ID:6309394

Groebner, R J; Burrell, K H; Gohil, P; Seraydarian, R P ^[1]

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1. General Atomics, San Diego, CA (USA)

Doppler-shift spectroscopy has shown that finite values of poloidal rotation velocity {ital v}{sub {theta}} and of radial electric field {ital E}{sub {ital r}} exist at the edge of a tokamak plasma and that dramatic increases occur in these parameters at an L-H transition. {ital E}{sub {ital r}} is negative in the L mode and becomes more negative in the H mode; {ital v}{sub {theta}} increases in magnitude at the transition. In addition, the radial gradients (shear) of {ital v}{sub {theta}} and {ital E}{sub {ital 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 {ital v}{sub {theta}} and {ital v}{sub {phi}} or of {ital v}{sub {perpendicular}} and {ital v}{sub {parallel}}. Knowledge of {ital v}{sub {perpendicular}} is used to calculate {ital E}{sub {ital 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 {ital v}{sub {theta}} and {ital E}{sub {ital r}} will be made with upgraded instrumentation, which is now coming on-line.

• DOE Contract Number: AC03-89ER51114
• OSTI ID: 6309394
• Journal Information: Review of Scientific Instruments; (USA), Journal Name: Review of Scientific Instruments; (USA) Vol. 61:10; ISSN RSINA; ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
CHARGED PARTICLES
CLOSED PLASMA DEVICES
DOPPLER EFFECT
DOUBLET-3 DEVICE
ELECTRIC FIELDS
HELIUM IONS
IONS
PLASMA DIAGNOSTICS
SPECTROSCOPY
THERMONUCLEAR DEVICES
TOKAMAK DEVICES