Understanding core tungsten (W) transport and control in an improved high-performance fully non-inductive discharge on EAST

作者：Shengyu Shi, Jiale Chen, C. Bourdelle, Xiang Jian, T. Odstrčil, Andrea M Garofalo, Yunxin Cheng, Yan Chao, Ling Zhang, Yanmin Duan, Muquan Wu, Fang Ding, Yingying Li, Juan Huang, Jinping Qian, Xiang Gao, Yuanxi Wan · 发表于：Nuclear Fusion · 年份：2021 · DOI：10.1088/1741-4326/ac3e3c · 被引用次数：28 · 研究领域：Magnetic confinement fusion research、Fusion materials and technologies、Laser-Plasma Interactions and Diagnostics

Abstract The behavior of heavy/high- Z impurity tungsten (W) in an improved high-performance fully non-inductive discharge on EAST with ITER-like divertor (ILD) is analyzed. It is found that W could be well controlled. The causes of no W accumulation are clarified by analyzing the background plasma parameters and modeling the W transport. It turns out that the electron temperature ( T e ) and its gradient are usually high while the toroidal rotation and density peaking of the bulk plasma are small. In this condition, the modeled W turbulent diffusion coefficient is big enough to offset the total turbulent and neoclassical pinch, so that W density profile for zero particle flux will not be very peaked. Combining NEO and TGLF for the W transport coefficient and the impurity transport code STRAHL, not only the core W density profile is predicted but also the radiated information mainly produced by W in the experiment can be closely reconstructed. At last, the physics of controlling W accumulation by electron cyclotron resonance heating (ECRH) is illustrated considering the effects of changed T e by ECRH on ionization balance and transport of W. It shows that the change of ionization and recombination balance by changed T e is not enough to explain the experimental observation of W behavior, which should be attributed to the changed W transport. By comparing the W transport coefficients in two kinds of plasmas with different T e profiles, it is shown that high T e and its gradien...