Progress of physics understanding for long pulse high-performance plasmas on EAST towards the steady-state operation of ITER and CFETR
Progress of physics understanding for long pulse high-performance plasmas on EAST towards the steady-state operation of ITER and CFETR
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DOI：
10.1088/1361-6587/ab56a5
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发表时间：
2019-12
影响因子：
2.2
通讯作者：
J. Huang;X. Gong;A. Garofalo;J. Qian;J. Chen;M. Wu;M. Li;Q. Yuan;Liang Wang;C. Pan-
中科院分区：
文献类型：
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作者：
J. Huang;X. Gong;A. Garofalo;J. Qian;J. Chen;M. Wu;M. Li;Q. Yuan;Liang Wang;C. Pan-
最近，在先进超导托卡马克实验装置(EAST)上，利用类似ITER(国际托卡马克实验堆)的钨上偏滤器，首次实现了对杂质、芯部和边缘磁流体稳定性以及散热的良好控制，首次实现了100个S长稳态H模放电。EAST使用射频(RF)功率和中性束注入(NBI)加热，展示了完全无感的场景，并在高密度和低旋转下扩展了融合性能：βP∼2.5、βN∼2.0、H98、y2∼1.2、自举电流分数FBS∼50%在q95∼6.8。在纯射频功率加热下，等离子体在高密度(Ne/NgW∼0.6-0.8)、βP∼2.0、βN∼1.6和ƒBS∼47%处保持了高达21个S(超过电流弛豫时间的40倍)和零环电压和小边缘局域模(ELM)。实验研究表明，等离子体电流分布、湍流输运和辐射特性如何自洽地向聚变相关的稳态条件演化。模拟和物理实验证实了电子回旋加热(ECH)和低杂波(LHW)之间的协同效应，其中ECH增强了LHW注入的加热和电流驱动，从而实现了在更高密度下的完全无感操作。小的/无ELMS有利于H模相的射频功率耦合，减少偏滤器的侵蚀。在较高的βP下观察到较低的钨浓度，且芯部为中空轮廓。采用主动辐射反馈控制，使偏滤器热流密度降低了40%，符合高β-P情景。EAST上的完全无感高性能实验具有电子加热主导、零/低NBI扭矩和类似ITER的钨偏滤器等特点，为ITER和中国聚变工程试验堆(CFETR)的成功运行做出了独特的贡献。
Recently, the first ever 100 s long, steady-state H-mode discharge with good control of impurities, core and edge MHD stabilities, and heat exhaust was demonstrated in the Experimental Advanced Superconducting Tokamak (EAST) using the ITER-like (International Tokamak Experimental Reactor) tungsten upper divertor. Using both radio frequency (RF) power and neutral beam injection (NBI) heating, EAST has demonstrated fully non-inductive scenarios with an extension of fusion performance at high density and low rotation: β P ∼ 2.5, β N ∼ 2.0, H98,y2 ∼ 1.2, bootstrap current fraction fBS ∼50% at q95 ∼ 6.8. With pure RF power heating, plasmas have been maintained for up to 21 s (over 40 times the current relaxation time) with zero loop voltage and small edge localized modes (ELMs) at high density (ne/nGW ∼ 0.6–0.8), β P ∼ 2.0, β N ∼ 1.6, and ƒBS ∼47%. Experimental investigations show how plasma current profiles, turbulent transport and radiation properties self-consistently evolve toward fusion relevant steady state conditions. Modeling and physics experiments have confirmed the synergistic effects between electron cyclotron heating (ECH) and low hybrid wave (LHW), where ECH enhances the heating and current drive from LHW injection, enabling fully non-inductive operation at higher density. Small/no ELMs facilitate the RF power coupling in the H-mode phase and reduce divertor erosion. A low tungsten concentration was observed at high β P with a hollow profile in the core. Reduction of the peak divertor heat flux with f rad of up to 40% was compatible with the high β P scenario by using active radiation feedback control. With features such as dominant electron heating, zero/low NBI torque and an ITER-like tungsten divertor, fully non-inductive high-performance experiments on EAST offer unique contributions towards the succesful operation of ITER and CFETR (the Chinese Fusion Engineering Testing Reactor).