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Varennes R, Garbet X, Vermare L, Sarazin Y, Dif-Pradalier G, Grandgirard V, Ghendrih P, Donnel P, Peret M, Obrejan K, Bourne E. Synergy of Turbulent Momentum Drive and Magnetic Braking. PHYSICAL REVIEW LETTERS 2022; 128:255002. [PMID: 35802431 DOI: 10.1103/physrevlett.128.255002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/17/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
In absence of external torque, plasma rotation in tokamaks results from a balance between collisional magnetic braking and turbulent drive. The outcome of this competition and cooperation is essential to determine the plasma flow. A reduced model, supported by gyrokinetic simulations, is first used to explain and quantify the competition only. The ripple amplitude above which magnetic drag overcomes turbulent viscosity is obtained. The synergetic impact of ripple on the turbulent toroidal Reynolds stress is explored. Simulations show that the main effect comes from an enhancement of the radial electric field shear by the ripple, which in turn impacts the residual stress.
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Affiliation(s)
- R Varennes
- CEA, IRFM, F-13108 Saint-Paul-Lez-Durance, France
| | - X Garbet
- CEA, IRFM, F-13108 Saint-Paul-Lez-Durance, France
| | - L Vermare
- LPP, CNRS, Ecole polytechnique, 91128 Palaiseau, France
| | - Y Sarazin
- CEA, IRFM, F-13108 Saint-Paul-Lez-Durance, France
| | | | | | - P Ghendrih
- CEA, IRFM, F-13108 Saint-Paul-Lez-Durance, France
| | - P Donnel
- CEA, IRFM, F-13108 Saint-Paul-Lez-Durance, France
| | - M Peret
- CEA, IRFM, F-13108 Saint-Paul-Lez-Durance, France
| | - K Obrejan
- CEA, IRFM, F-13108 Saint-Paul-Lez-Durance, France
| | - E Bourne
- CEA, IRFM, F-13108 Saint-Paul-Lez-Durance, France
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Poloidal Rotation and Edge Ion Temperature Measurements Using Spectroscopy Diagnostic on Aditya-U Tokamak. ATOMS 2019. [DOI: 10.3390/atoms7030093] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The impurity ion poloidal rotation and ion temperature from the Aditya-U tokamak plasma have been measured using a high-resolution spectroscopic diagnostic. It comprises of a high resolution, 1 m, f/8.7, Czerny-Turner configuration spectrometer along with charge coupled device (CCD) detector. The system monitors the spectral line emission of C2+ impurity ions at 464.74 nm from the top port of the Aditya-U vacuum vessel with the lines of sight covering the plasma minor radius from r = 11.55 cm to 21.55 cm. The impurity ion poloidal rotation velocity and temperature have been estimated using the Doppler shift and Doppler broadening of the spectral lines respectively. The maximum poloidal rotation at a radial location of 21.55 cm in the edge of the plasma during the plasma current flat top was observed to be ~4 km/s for the analyzed discharges and the ion temperatures measured in the edge were in the range of 32–40 eV.
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Shukla G, Chowdhuri MB, Shah K, Manchanda R, Mayya KBK, Ghosh J. Plasma rotation measurement using UV and visible spectroscopy on Aditya-U tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10D132. [PMID: 30399770 DOI: 10.1063/1.5039333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 09/12/2018] [Indexed: 06/08/2023]
Abstract
A high resolution spectroscopic diagnostic for the measurement of the spatial profile of toroidal rotation velocity (vt) and temperature (Ti) of carbon ions has been developed and implemented on the Aditya-U tokamak. The diagnostic consists of a high resolution 1 m (f/8.7) spectrometer having an 1800 grooves/mm grating coupled with a charged couple device. The setup allows measurements from 5 toroidal lines-of-sights passing through different minor radii in the horizontal mid-plane of the Aditya-U tokamak. The carbon line emissions at 529 nm in visible and 229.6 and 227.09 nm in the ultra violet spectral range are recorded using the setup. Initial results show that typical Aditya-U plasmas have a maximum carbon ion temperature (Ti) of ∼120 eV and a rotation velocity (vt) of ∼-14 km/s in the counter plasma-current direction.
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Affiliation(s)
- G Shukla
- Department of Science, Pandit Deendayal Petroleum University, Gandhinagar 382 421, India
| | - M B Chowdhuri
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - K Shah
- Department of Science, Pandit Deendayal Petroleum University, Gandhinagar 382 421, India
| | - R Manchanda
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - K B K Mayya
- Department of Science, Pandit Deendayal Petroleum University, Gandhinagar 382 421, India
| | - J Ghosh
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
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Cheng ZF, Luo J, Wang ZJ, Zhang ZP, Zhang XL, Hou SY, Cheng C, Li Z, Zhuang G. Edge impurity rotation profile measurement by using high-resolution ultraviolet/visible spectrometer on J-TEXT. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11E423. [PMID: 25430330 DOI: 10.1063/1.4891927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
An upgrade of the edge rotation diagnostic system is achieved by increasing the number of viewing channels to 17 on J-TEXT tokamak. With the upgrade, the spatial resolution reaches 1 cm. The bulk plasma is used as the calibration light source. And the toroidal velocity profile of C V (carbon V) at edge region is obtained by using a spatial deconvolution technique. The valid measurement region is at ρ = 0.6-0.9, corresponding to the emitting region of C V. The preliminary experimental results express that the velocity of plasma may have a zero point near ρ = 0.85.
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Affiliation(s)
- Z F Cheng
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - J Luo
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Z J Wang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Z P Zhang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - X L Zhang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - S Y Hou
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - C Cheng
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Z Li
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - G Zhuang
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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Kabantsev AA, Dubin DHE, Driscoll CF, Tsidulko YA. Chaotic transport and damping from θ-ruffled separatrices. PHYSICAL REVIEW LETTERS 2010; 105:205001. [PMID: 21231239 DOI: 10.1103/physrevlett.105.205001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Indexed: 05/30/2023]
Abstract
Variations in magnetic or electrostatic confinement fields give rise to trapping separatrices, and neoclassical transport theory analyzes effects from collision-induced separatrix crossings. Experiments on pure electron plasmas now quantitatively characterize a broad range of transport and wave damping effects due to "chaotic" separatrix crossings, which occur due to equilibrium plasma rotation across θ-ruffled separatrices, and due to wave-induced separatrix fluctuations.
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Affiliation(s)
- A A Kabantsev
- Department of Physics, University of California, San Diego, California, USA
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