Tokamak fusion test reactor poloidal rotation diagnostic (invited)
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)
A new spectroscopic diagnostic was developed to measure poloidal velocity profiles of Tokamak fusion test reactor (TFTR) plasmas. Carbon poloidal velocities were measured using the Doppler shift of the CthinspVI 5291 {Angstrom} impurity line of both intrinsic emission and charge exchange emission from neutral beams. Poloidal velocities are typically small (v{sub {theta}}{le}10{sup 4}thinspm/s) requiring small wavelength shifts ({Delta}{lambda}{le}0.2thinsp{Angstrom}) to be measured. However, the high central ion temperatures in TFTR required the use of a low dispersion spectrometer to view the entire linewidth (full width at half maximum {le}25 {Angstrom}). A very high throughput spectrometer/detector system was assembled to achieve the necessary precision in v{sub {theta}}. Statistical errors in the chord-averaged poloidal velocity less than 100 m/s have been obtained. The short focal length spectrometer features f/1.8 input optics, a transmission grating, and refractive optics. A thinned back-illuminated charge coupled device detector provided a high quantum efficiency (QE=75{percent}). The diagnostic had 20 ms time resolution and a radial resolution of {le}3.5 cm after an inversion. Two symmetric up/down views were used to eliminate atomic physics effects that would otherwise distort the measured rotation velocity. This diagnostic complemented the measurements of T{sub i}, v{sub {phi}}, and n{sub i} from a charge exchange spectroscopy system, allowing the determination of radial electric field profiles using the force balance equation. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 295658
- Report Number(s):
- CONF-980605--
- Journal Information:
- Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 1 Vol. 70; ISSN 0034-6748; ISSN RSINAK
- Country of Publication:
- United States
- Language:
- English
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