Observations of toroidal plasma rotation reversal in the Aditya-U tokamak. (9th September 2019)

• Record Type: Journal Article
• Authors: Shukla, G.; Shah, K.; Chowdhuri, M.B.; Raj, H.; Macwan, T.; Manchanda, R.; Nagora, U.C.; Tanna, R.L.; Jadeja, K.A.; Patel, K.; Mayya, K.B.K.; Atrey, P.K.; Ghosh, J.
• Other Names: collab.
• Is Part Of: Nuclear fusion. Volume 59:Number 10(2019:Oct.)
• Publication Date: 2019-09-09
• Subjects: toroidal rotation -- rotation reversal -- Doppler shift spectroscopy -- tokamak; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/1741-4326/ab3518
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: An impurity ion toroidal rotation profile has been observed in the ohmic discharges of the Aditya-U tokamak from the Doppler-shifted passive charge exchange line emission of C 5+ at 529 nm. The line has been monitored using a space-resolved visible spectroscopy diagnostic consisting of a 1 m multi-track spectrometer coupled with a charge coupled device (CCD) detector. In typical discharges with central chord-averaged electron density ≲2.5 × 10 19 m −3, the maximum toroidal rotation velocity at the plasma core is found to be −20 km s −1 in the counter-current direction. Reversal of plasma toroidal rotation is observed for high electron density discharges with a central chord-averaged density of ~5 × 10 19 m −3 . During the rotation reversal, the direction of toroidal rotation changes to the co-current direction in the core. Interestingly, in the discharges with a central chord-averaged electron density of ≲2.5 × 10 19 m −3, where neon gas is injected at the plasma current flat-top, the toroidal rotation reversal has been observed after the gas puff.