Plasma-surface interaction in the Be/W environment: Conclusions drawn from the JET-ILW for ITER
Plasma-surface interaction in the Be/W environment: Conclusions drawn from the JET-ILW for ITER
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DOI：
10.1016/j.jnucmat.2014.12.007
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发表时间：
2015-08-01
影响因子：
3.1
通讯作者：
Brezinsek, S.
中科院分区：
文献类型：
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作者：
Brezinsek, S.
JET ITER类壁实验（JET-ILW）提供了一个理想的测试平台，以研究等离子体表面相互作用（PSI）和等离子体操作与ITER面向等离子体的材料选择，采用铍在主室和钨偏滤器。PSI的主要流程：对JET-C和JET-ILW的材料侵蚀和迁移、燃料再循环和滞留、杂质浓度和辐射特性进行了研究和比较。当前对JET-ILW中这些关键过程的物理学理解表明，需要重新审视对先前获得的碳结果（JET-C）的解释和对ITER的预测。第一壁材料对等离子体的影响被低估，主要观察结果是：（a）H模式等离子体中的初级侵蚀源较低，从主腔室到偏滤器的材料迁移减少（系数7），以及在偏滤器内从面向等离子体的区域到偏远区域的材料迁移减少（系数30 - 50）。铍溅射的能量阈值使主要侵蚀源最小化，并抑制偏滤器中的多步再侵蚀。钨的物理溅射产额低至10（-5），由铍离子决定。(b)与JET-C相比，JET-ILW的长期燃油保持率降低（系数10 - 20）。剩余的保留是由铍和残留杂质的注入和共沉积引起的。除气已经获得了重要性，并对铍和钨的回收性能产生影响。(c)铍的低有效等离子体电荷（Z（eff）= 1.2）和低辐射能力揭示了裸露的氘等离子体物理。达到Z（eff）= 1.6的适度氮播种特别恢复限制和L-H阈值行为。由于ILW的密度限制较高，因此获得了ITER兼容的偏滤器条件（具有稳定的半脱离）。总体而言，JET在Be/W材料组合中成功地展示了等离子体操作，并证实了其有利的PSI行为，并为ITER材料选择提供了强有力的支持。(C)2014作者由Elsevier B. V.出版，这是CC BY-NC-ND许可下的开放获取文章。
The JET ITER-Like Wall experiment (JET-ILW) provides an ideal test bed to investigate plasma-surface interaction (PSI) and plasma operation with the ITER plasma-facing material selection employing beryllium in the main chamber and tungsten in the divertor. The main PSI processes: material erosion and migration, (b) fuel recycling and retention, (c) impurity concentration and radiation have bel en studied and compared between JET-C and JET-ILW. The current physics understanding of these key processes in the JET-ILW revealed that both interpretation of previously obtained carbon results (JET-C) and predictions to ITER need to be revisited. The impact of the first-wall material on the plasma was underestimated.Main observations are: (a) low primary erosion source in H-mode plasmas and reduction of the material migration from the main chamber to the divertor (factor 7) as well as within the divertor from plasma-facing to remote areas (factor 30 - 50). The energetic threshold for beryllium sputtering minimises the primary erosion source and inhibits multi-step re-erosion in the divertor. The physical sputtering yield of tungsten is low as 10(-5) and determined by beryllium ions. (b) Reduction of the long-term fuel retention (factor 10 - 20) in JET-ILW with respect to JET-C. The remaining retention is caused by implantation and co-deposition with beryllium and residual impurities. Outgassing has gained importance and impacts on the recycling properties of beryllium and tungsten. (c) The low effective plasma charge (Z(eff) = 1.2) and low radiation capability of beryllium reveal the bare deuterium plasma physics. Moderate nitrogen seeding, reaching Z(eff) = 1.6, restores in particular the confinement and the L-H threshold behaviour. ITER-compatible divertor conditions with stable semi-detachment were obtained owing to a higher density limit with ILW. Overall JET demonstrated successful plasma operation in the Be/W material combination and confirms its advantageous PSI behaviour and gives strong support to the ITER material selection. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.