Predictive multi-channel integrated modeling of a reversed magnetic shear H-mode discharge with internal transport barrier in EAST
Predictive multi-channel integrated modeling of a reversed magnetic shear H-mode discharge with internal transport barrier in EAST
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DOI：
10.1088/1741-4326/ac32f0
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发表时间：
2021-10
期刊：
影响因子：
3.3
通讯作者：
S. Shi;Jiale Chen;C. Bourdelle;X. Jian;Ming-Shan Wu;Tao Zhang;J. Qian;A. Garofalo;Xiang Gao
中科院分区：
文献类型：
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作者：
S. Shi;Jiale Chen;C. Bourdelle;X. Jian;Ming-Shan Wu;Tao Zhang;J. Qian;A. Garofalo;Xiang Gao
在实验先进超导托卡马克装置（EAST）上实现了具有内输运势垒（ITB）的反向磁剪切高等离子体性能H模放电，并模拟了带有类ITER钨（W）上偏滤器的氘（D）等离子体。在该炮（#71326）中，无量纲参数G（H89βN/q952）可达0.25（H 89 <$2，β N <$2，q95 <$4，Ip <$450 kA，B T <$1.6 T）。在粒子（电子密度ne）、电子和离子温度（Te和Ti）以及环向旋转速度（Vt）通道中观察到了ITB。然而，在Vt和neITB的形成过程中，重杂质在芯等离子体中积累，这可能是限制等离子体性能提高的重要原因之一。分析了高等离子体性能阶段的时间片（t = 4.65 s），其中n e，Ti和Vt ITB。结果表明，在利用外磁和内旋光干涉仪（POINT）测量约束进行EFIT平衡重建时，最小安全系数（qmin）的位置约在归一化半径ρ = 0.4处，这可能是离子ITB足的位置。在此基础上，用ONETWO和NUBEAM自洽地计算了源。在此基础上，首次在EAST上利用重建的平衡态、自洽源和实验辐射功率，用TGYRO对n e、Te、Ti和Vt进行了预测性的同时建模。该模型很好地再现了反向磁剪切等离子体中的实验ne和Ti分布。此外，还表明，主要由Vt产生的径向电场（Er）的反向磁剪切而不是剪切对ne和Ti ITBs的形成起着关键作用.通过计算W的新经典输运分量和湍流输运分量，阐明了W杂质中心聚集的原因。结果表明，新经典输运对W的湍流输运起主导作用，W的新经典箍缩导致W的中心积累。
A reversed magnetic shear high plasma performance H-mode discharge with internal transport barrier (ITB) has been realized and modeled on experimental advanced superconducting tokamak (EAST) in deuterium (D) plasmas with an ITER-like tungsten (W) upper divertor. In this shot (#71326), the dimensionless parameter G ( H89βN/q952 ) can reach to 0.25 (H 89 ⩽ 2, β N ⩽ 2, q 95 ∼ 4, I p ⩽ 450 kA, B T ⩽ 1.6 T). The ITB has been observed in the channels of particle (electron density n e), electron and ion temperature (T e and T i) and toroidal rotation velocity (V t). However, in the formation process of V t and n e ITBs, the heavy impurities accumulate in the core plasmas, which may be one of the most important reasons for the limitation of the improvement of plasma performance. A time slice (t = 4.65 s) of the high plasma performance phase with n e, T i and V t ITBs has been analyzed. It is found that the position of minimum safety factor (q min) is at about normalized radius ρ = 0.4 where may be the location of ion ITB foot, during equilibrium reconstruction from EFIT using external magnetic and internal polarimeter-INTferometer (POINT) measurement constraints. Based on this equilibrium, the source is self-consistently calculated by ONETWO and NUBEAM. Then the n e, T e, T i and V t have been modeled predictively and simultaneously by TGYRO utilizing the reconstructed equilibrium, the self-consistent source and the experimental radiated power for the first time in EAST. This modeling well reproduces the experimental n e and T i profiles in the reversed magnetic shear plasmas. In addition, it is shown that reversed magnetic shear rather than shear of radial electric field (E r) mainly produced by V t plays a key role to the formation of n e and T i ITBs. The reasons for central accumulation of W impurity are also clarified by computing both neoclassical and turbulent transport components of W. It turns out that the neoclassical transport dominates over turbulent transport for W and neoclassical pinch of W causes its central accumulation.