Nuclear Fusion (Jan 2024)
The role of shear flow collapse and enhanced turbulence spreading in edge cooling approaching the density limit
- Ting Long,
- P.H. Diamond,
- Rui Ke,
- Zhipeng Chen,
- Xin Xu,
- Wenjing Tian,
- Rongjie Hong,
- Mingyun Cao,
- Yanmin Liu,
- Min Xu,
- Lu Wang,
- Zhoujun Yang,
- Jinbang Yuan,
- Yongkang Zhou,
- Qinghao Yan,
- Qinghu Yang,
- Chengshuo Shen,
- Lin Nie,
- Zhanhui Wang,
- Guangzhou Hao,
- Nengchao Wang,
- Zhongyong Chen,
- Jiquan Li,
- Wei Chen,
- Wulyu Zhong
Affiliations
- Ting Long
- ORCiD
- Southwestern Institute of Physics , Chengdu 610225, China
- P.H. Diamond
- ORCiD
- Departments of Astronomy, Astrophysics and Physics, University of California , San Diego, CA 92093, United States of America
- Rui Ke
- ORCiD
- Southwestern Institute of Physics , Chengdu 610225, China
- Zhipeng Chen
- ORCiD
- State Key Laboratory of Advanced Electromagnetic Technology, International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
- Xin Xu
- State Key Laboratory of Advanced Electromagnetic Technology, International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
- Wenjing Tian
- Southwestern Institute of Physics , Chengdu 610225, China; Tsinghua University , Beijing 100084, China
- Rongjie Hong
- ORCiD
- University of California , Los Angeles, CA 90095, United States of America
- Mingyun Cao
- ORCiD
- Departments of Astronomy, Astrophysics and Physics, University of California , San Diego, CA 92093, United States of America
- Yanmin Liu
- Southwestern Institute of Physics , Chengdu 610225, China
- Min Xu
- Southwestern Institute of Physics , Chengdu 610225, China
- Lu Wang
- ORCiD
- State Key Laboratory of Advanced Electromagnetic Technology, International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
- Zhoujun Yang
- ORCiD
- State Key Laboratory of Advanced Electromagnetic Technology, International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
- Jinbang Yuan
- ORCiD
- Southwestern Institute of Physics , Chengdu 610225, China
- Yongkang Zhou
- Southwestern Institute of Physics , Chengdu 610225, China; Department of Plasma Physics and Fusion Engineering, University of Science and Technology of China , Hefei 230026, China
- Qinghao Yan
- Southwestern Institute of Physics , Chengdu 610225, China
- Qinghu Yang
- State Key Laboratory of Advanced Electromagnetic Technology, International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
- Chengshuo Shen
- State Key Laboratory of Advanced Electromagnetic Technology, International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
- Lin Nie
- Southwestern Institute of Physics , Chengdu 610225, China
- Zhanhui Wang
- Southwestern Institute of Physics , Chengdu 610225, China
- Guangzhou Hao
- ORCiD
- Southwestern Institute of Physics , Chengdu 610225, China
- Nengchao Wang
- ORCiD
- State Key Laboratory of Advanced Electromagnetic Technology, International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
- Zhongyong Chen
- ORCiD
- State Key Laboratory of Advanced Electromagnetic Technology, International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
- Jiquan Li
- Southwestern Institute of Physics , Chengdu 610225, China
- Wei Chen
- ORCiD
- Southwestern Institute of Physics , Chengdu 610225, China
- Wulyu Zhong
- Southwestern Institute of Physics , Chengdu 610225, China
- DOI
- https://doi.org/10.1088/1741-4326/ad3e15
- Journal volume & issue
-
Vol. 64,
no. 6
p. 066011
Abstract
Experimental studies of the dynamics of shear flow and turbulence spreading at the edge of tokamak plasmas are reported. Scans of line-averaged density and plasma current are carried out while approaching the Greenwald density limit on the J-TEXT tokamak. In all scans, when the Greenwald fraction ${f_{\text{G}}} = {{\bar n} \mathord{\left/ \right. } {{n_{\text{G}}}}} = {{\bar n} \mathord{\left/ \right. } {\left( {{{{I_{\text{p}}}} \mathord{\left/ \right. } {\pi {a^2}}}} \right)}}$ increases, a common feature of enhanced turbulence spreading and edge cooling is found. The result suggests that turbulence spreading is a good indicator of edge cooling, indeed better than turbulent particle transport is. The normalized turbulence spreading power increases significantly when the normalized ${\boldsymbol{E}} \times {\boldsymbol{B}}$ shearing rate decreases. This indicates that turbulence spreading becomes prominent when the shearing rate is weaker than the turbulence scattering rate. The asymmetry between positive/negative (blobs/holes) spreading events, turbulence spreading power and shear flow are discussed. These results elucidate the important effects of interaction between shear flow and turbulence spreading on plasma edge cooling.
Keywords
