Physics design of new lower tungsten divertor for long-pulse high-power operations in EAST

作者：Guosheng Xu, Liang Wang, Damao Yao, Guozhang Jia, Chaofeng Sang, Xiaoju Liu, Y.P. Chen, Hang Si, Z.S. Yang, Huan Guo, Hong Du, Zhengping Luo, Hao Li, Zibo Zhou, L. Cao, H.C. Xu, Tiejun Xu, Zhongli Wang, Pengfei Zi, L. Li, Le Han, J.C. Xu, J.B. Liu, Kedong Li, Bin Cao, Yaowei Yu, Fangyu Ding, Rui Ding, N. Yan, L.Y. Meng, Y.Q. Tao, Huiqian Wang, Y. Zhang, L.M. Shao, X.D. Zhang, S.Z. Zhu, Baonian Wan, the EAST Team · 发表于：Nuclear Fusion · 年份：2021 · DOI：10.1088/1741-4326/ac3297 · 被引用次数：90 · 研究领域：Magnetic confinement fusion research、Fusion materials and technologies、Particle accelerators and beam dynamics

Abstract A new lower tungsten divertor has been developed and installed in the EAST superconducting tokamak to replace the previous graphite divertor with power handling capability increasing from <2 MW m −2 to ∼10 MW m −2 , aiming at achieving long-pulse H-mode operations in a full metal wall environment with the steady-state divertor heat flux of ∼10 MW m −2 . A new divertor concept, ‘corner slot’ (CS) divertor, has been employed. By using the ‘corner effect’, a strongly dissipative divertor with the local buildup of high neutral pressure near the corner can be achieved, so that stable detachment can be maintained across the entire outer target plate with a relatively lower impurity seeding rate, at a separatrix density compatible with advanced steady-state core scenarios. These are essential for achieving efficient current drive with low-hybrid waves, a low core impurity concentration and thus a low loop voltage for fully non-inductive long-pulse operations. Compared with the highly closed small-angle-slot divertor in DIII-D, the new divertor in EAST exhibits the following merits: (1) a much simpler geometry with integral cassette body structure, combining vertical and horizontal target plates, which are more suitable for actively water-cooled W/Cu plasma facing components, facilitating installation precision control for minimizing surface misalignment, achieving high engineering reliability and lowering the capital cost as well; (2) it has much greater flexibility in m...