Observation of Double Impurity Critical Gradients for Electromagnetic Turbulence Excitation in Tokamak Plasmas

The impact of impurity ions on a pedestal has been investigated in the HL-2A Tokamak, at the Southwestern Institute of Physics, Chengdu, China. Experimental results have clearly shown that during the H-mode phase, an electromagnetic turbulence was excited in the edge plasma region, where the impurit...

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Bibliographic Details
Published in:Physical review letters 2016-07, Vol.117 (4), p.045001-045001, Article 045001
Main Authors: Zhong, W L, Shen, Y, Zou, X L, Gao, J M, Shi, Z B, Dong, J Q, Duan, X R, Xu, M, Cui, Z Y, Li, Y G, Ji, X Q, Yu, D L, Cheng, J, Xiao, G L, Jiang, M, Yang, Z C, Zhang, B Y, Shi, P W, Liu, Z T, Song, X M, Ding, X T, Liu, Yong
Format: Article
Language:English
Subjects:
Excitation
Fluid dynamics
Fluid flow
Impurities
Plasmas
Tokamak devices
Turbulence
Turbulent flow
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Summary:The impact of impurity ions on a pedestal has been investigated in the HL-2A Tokamak, at the Southwestern Institute of Physics, Chengdu, China. Experimental results have clearly shown that during the H-mode phase, an electromagnetic turbulence was excited in the edge plasma region, where the impurity ions exhibited a peaked profile. It has been found that double impurity critical gradients are responsible for triggering the turbulence. Strong stiffness of the impurity profile has been observed during cyclic transitions between the I-phase and H-mode regime. The results suggest that the underlying physics of the self-regulated edge impurity profile offers the possibility for an active control of the pedestal dynamics via pedestal turbulence.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.117.045001