Measurement of toroidal and poloidal plasma rotation in TCA
The toroidal and poloidal plasma rotation velocities have been studied in TCA under various plasma conditions. The velocities are determined by spectroscopic measurements of the Doppler shift of intrinsic or injected impurity line emission. A visible 1 m Czerny-Turner spectrometer coupled to an optical multichannel analyser is used to follow the temporal evolution of the impurity radiation with a time resolution of 2 ms. The rotation is observed at the edge of the plasma using HeII and CIII lines, and further inside the plasma with a CV line radiating at r/a = 0.6. The rotation is measured in ohmically heated discharges as a function of density up to the density limit, and as a function of the rate of increase of density. A toroidal rotation velocity of 5 km/s is measured in the direction of the plasma current and magnetic field. This velocity decreases with increasing density and becomes very close to zero or even reverses sign at high density. In contrast, the poloidal velocity, which is of the same order of magnitude, increases with density. These two effects correspond to an increased radial electric field. This paper also presents results obtained during Alfvén wave heating. Despite the effect of the density increase associated with the rf pulse, there is evidence of an additional variation in the edge plasma rotation which depends on the rf spectrum.
Bibliographic Reference: Paper presented: 18th European Conference on Controlled Fusion and Plasma Physics, Berlin (DE), June 3-7, 1991
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Record Number: 199110446 / Last updated on: 1994-12-02
Original language: en
Available languages: en