Advances in physics and applications of 3D magnetic perturbations on the J-TEXT tokamak

Nuclear Fushion

article

Nengchao Wang¹  Y. Liang¹  Yonghua Ding¹  Zhongyong Chen¹  Zhipeng Chen¹  Zhoujun Yang¹  Donghui Xia¹  Wei Zheng¹  Wei Yan¹  Da Li¹  Zhonghe Jiang¹  Lu Wang¹  Bo Rao¹  Qiming Hu⁴  Xiaolong Zhang⁵  Junli Zhang¹  Xixuan Chen¹  Xin Xu¹  Tao Xu¹  Xianli Xie¹  Zhuo Huang¹  Feiyue Mao¹  Dongliang Han¹  Jianchao Li⁶  Tong Wang¹  Linzi Liu¹  Ruihai Tong¹  Zhifang Lin¹  Yunong Wei¹  Nianheng Cai¹  Yuejiang Shi⁹  Yaping Zhang¹  Weixin Guo¹  Xiaoqing Zhang¹  Peng Shi^1,10  Zhifeng Cheng¹  Ping Zhu¹  Minghai Liu¹  Shaoxiang Ma¹  Yong Yang¹  Chuan Li¹  Li Gao¹  Zhijiang Wang¹  Ming Zhang¹  Kexun Yu¹  Xiwei Hu¹  Q. Yu^1,11  K.W. Gentle^1,12  Yuan Pan¹ 

[1] International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics ,(IFPP), State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology;Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung—Plasmaphysik;Institute of Plasma Physics, Chinese Academy of Sciences;Princeton Plasma Physics Laboratory, PO Box 451, Princeton;Advanced Energy Research Center, Shenzhen University;Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology;Southwestern Institute of Physics;Jiangsu Normal University, School of Electrical Engineering & Automation;Hebei Key Laboratory of Compact Fusion;United Kingdom Atomic Energy Authority ,(CCFE), Culham Science Centre;Max-Planck-Institut für Plasmaphysik;Institute of Fusion Studies, University of Texas at Austin

关键词: J-TEXT tokamak;    ECRH;    resonant magnetic perturbation;    disruption control;    divertor;    turbulence;   

DOI  :  10.1088/1741-4326/ac3aff

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

In the last two years, three major technical improvements have been made on J-TEXT in supporting of the expanded operation regions and diagnostic capabilities. (1) The successful commission of the 105 GHz/500 kW/1 s electron cyclotron resonance heating (ECRH) system increasing the core electron temperature from 0.9 keV up to around 1.5 keV. (2) The poloidal divertor configuration with anX -point in the high-field side has been achieved. In particular, the 400 kW electron cyclotron wave has also been successfully injected into the diverted plasma. (3) A 256-channel electron cyclotron emission imaging diagnostic system and two sets of four-channel Doppler backscattering diagnostics have been successfully developed on J-TEXT, allowing detailed measurement of the electron temperature and density fluctuations for turbulence and MHD research. The locked mode (LM), especially the 2/1 LM, is one of the biggest threats to the plasma operation. Both the thresholds of 2/1 and 3/1 LM are observed to vary non-monotonically on electron density. The electrode biasing was applied successfully to unlock the LM from either a rotating or static resonant magnetic perturbation (RMP) field. In the presence of 2/1 LM, three kinds of standing wave (SW) structures have been observed to share a similar connection to the island structure, i.e. the nodes of the SWs locate around theO - orX -points of the 2/1 island. The control and mitigation of disruption is essential to the safe operation of ITER, and it has been systematically studied by applying a RMP field, massive gas injection (MGI) and shattered pellet injection on J-TEXT. When the RMP-induced 2/1 LM is larger than a critical width, the MGI shutdown process can be significantly influenced. If the phase difference between theO -point of LM and the MGI valve is +90° (or −90°), the penetration depth and the assimilation of impurities can be enhanced (or suppressed) during the pre-thermal quench (TQ) phase and result in a faster (or slower) TQ. A secondary MGI can also suppress the runaway electron (RE) generation, if the additional high-Z impurity gas arrives at the plasma edge before TQ. When the secondary MGI has been applied after the formation of the RE current plateau, the RE current can be dissipated, and the dissipation rate increases with the injected impurity quantity but saturates with a maximum of 28 MA s⁻¹. The non-local transport is experimentally observed in the ion transport channel. The electron thermal diffusivity significantly increases with the ECRH power. Theoretical work shows that significant intrinsic current can be driven by electromagnetic turbulence, and the robust formation mechanism of theE × Bstaircase is identified from the Hasegawa–Wakatani system.

【 授权许可】

Unknown