title: Observation of Double Impurity Critical Gradients for Electromagnetic Turbulence Excitation in Tokamak Plasmas.
abstract: 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.
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: W L
authors: WL
authors: Zhong
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: Y
authors: Y
authors: Shen
authors: CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France.
authors: X L
authors: XL
authors: Zou
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: J M
authors: JM
authors: Gao
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: Z B
authors: ZB
authors: Shi
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.|Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027, People's Republic of China.
authors: J Q
authors: JQ
authors: Dong
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: X R
authors: XR
authors: Duan
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: M
authors: M
authors: Xu
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: Z Y
authors: ZY
authors: Cui
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: Y G
authors: YG
authors: Li
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: X Q
authors: XQ
authors: Ji
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: D L
authors: DL
authors: Yu
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: J
authors: J
authors: Cheng
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: G L
authors: GL
authors: Xiao
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: M
authors: M
authors: Jiang
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: Z C
authors: ZC
authors: Yang
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: B Y
authors: BY
authors: Zhang
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: P W
authors: PW
authors: Shi
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: Z T
authors: ZT
authors: Liu
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: X M
authors: XM
authors: Song
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: X T
authors: XT
authors: Ding
authors: Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China.
authors: Yong
authors: Y
authors: Liu