Article title: Tungsten control in type-I ELMy H-mode plasmas on EAST

文章题目：EAST上I型ELMy 高模等离子体中的钨控制

DOI:10.1007/s41365-021-00929-4 

One sentence summary:

一句话概要：

Tungsten concentration and accumulation in the EAST can now be controlled effectively.

EAST上钨的聚集现已得到有效控制。

http://www.nst.sinap.ac.cn/newsDetails/112/17389/en/

The Novelty (What)

创新性（主要内容）

Via experimental investigation on the Experimental Advanced Superconduction Tokamak (EAST), this study reported how the behavior of tungsten (in ELMy H-mode plasmas) could be controlled by neutral beam injection (NBI) and toroidal field (B_t). The concentration of tungsten in the plasma operation was successfully lowered by applying counter-NBI and favorable B_t. For preventing tungsten accumulation, it was a must for the tungsten concentration to be kept below 10^–4 to avoid degradation of plasma confinement and periodic H–L transitions. Future in-depth studies could be carried out to better understand the implications of increased turbulent transport (during the co/counter-NBI phases) on the suppression of tungsten accumulation.

通过在EAST实验装置上的实验研究,报道了中性束注入(NBI)和环向场(Bt)对钨在ELMy H模等离子体中的行为的控制。 应用反NBI和有利的BT,成功地降低了等离子体操作中的钨浓度。 为了防止钨的积累，必须将钨的浓度保持在10^–4以下，以避免等离子体约束的退化和周期性的H-L跃迁。 今后的深入研究可以更好地理解湍流输运增加（在CO/反NBI相期间）对抑制钨积累的影响。

The Background (Why)

研究背景（主要原因）

Despite being preferred for plasma-facing materials in fusion devices, tungsten tends to accumulate in the core plasma when it reaches a higher concentration. Among the adverse outcomes caused by such accumulation include disruption, loss of radiation, and degradation of energy confinement. Meanwhile, literature indicates that tungsten accumulation could be suppressed by controlling the neoclassical transport, inward pinch of high-Z impurities (PHZ), and radial electric field (E_r). Furthermore, these three variables were associated with NBI. Thus, this study focused on the potential of NBI in manipulating tungsten behavior in the core of an EAST type-I ELMy H-mode plasma, a mode that led to strong impurity accumulation in EAST. By mastering the technique to avoid tungsten accumulation, the EAST will be able to perform more optimally.

尽管钨在聚变装置中作为面向等离子体的材料是优选的，但当钨达到较高浓度时，它倾向于积聚在堆芯等离子体中。 这种积累造成的不良后果包括破坏、辐射损失和能量限制的退化。 同时，文献表明，控制新经典输运、高Z杂质向内箍缩(PHZ)和径向电场(Er)可以抑制钨的积累。 此外，这三个变量都与NBI相关。 因此，本研究着重于NBI在EAST I型ELMy H模等离子体核心中控制钨行为的潜力，该模式导致EAST中强杂质积聚。 通过掌握避免钨堆积的技术，EAST将能够表现得更加优化。

The SDG impact (Big Why)

SDG影响力（研究意义）

As the first Tokamak with superconducting toroidal and poloidal magnets, the EAST is a valuable facility for nuclear fusion and plasma research. Thus, its performance stability and consistency are a top priority. By exploring effective methods to minimize tungsten accumulation in the EAST, this research showcased efforts that aligned with the targets of UNSDG 9: Industry, Innovation & Infrastructure.

作为第一个拥有超导环向和极向磁体的托卡马克，EAST是核聚变和等离子体研究的宝贵设施。 因此，其性能的稳定性和一致性是重中之重。 通过探索最大限度地减少EAST上钨积累的有效方法，这项研究显示了与联合国可持续发展目标9（工业、创新和基础设施）的目标相一致的努力。