Effects of nitrogen-seeded deuterium plasma on tungsten surfaces
Effects of nitrogen-seeded deuterium plasma on tungsten surfaces
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DOI：
10.1088/1741-4326/ab0142
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发表时间：
2019-02
期刊：
影响因子：
3.3
通讯作者：
S. Takamura;T. Aota;Y. Uesugi;Y. Kikuchi;S. Maenaka;K. Fujita
中科院分区：
文献类型：
--
作者：
S. Takamura;T. Aota;Y. Uesugi;Y. Kikuchi;S. Maenaka;K. Fujita
由于等离子体热通量巨大，钨等靶材料的熔化和蒸发与ITER（国际热核聚变实验堆）和核聚变反应堆设计的实现是不相容的。近年来，氮气引晶被认为是边缘和偏滤器边界等离子体的有效辐射体，以防止偏滤器板过热。虽然在现有的托卡马克装置中，氮籽晶与托卡马克放电操作是相容的，但氮籽晶对面向等离子体的部件，特别是偏滤器靶材料的影响，（例如钨），尚未在具有高等离子体密度和等离子体热通量的与聚变相关的稳态线性等离子体系统中进行充分测试，其中氘和氮混合气体放电等离子体被照射到钨靶上，这与磁聚变结构中的边界区域非常相似。这项研究解决了这样一个详细的照射，使用各种表面分析。表面温度敏感的氮化钨的形成被确定，从而阐明了有趣的表面形貌的晶须，环，和/或钩状纳米结构在一些表面温度带。使用几种表面分析方法，包括X-射线衍射，能量色散X-射线分析，纳米压痕，拉曼光谱，和光谱测定的表面特性。钨污染到面临的等离子体的可能性进行了讨论，在氮化钨熔化。还提到了氮化钨与工业应用的关系。
The melting and evaporation of target materials such as tungsten, due to the enormous plasma heat flux, are not compatible with the realization of ITER (International Thermonuclear Experimental Reactor) and nuclear fusion reactor designs. Nitrogen gas seeding has recently been considered as an effective radiator for edge and divertor boundary plasmas to protect the divertor plate from overheating. Although compatibility of nitrogen seeding with tokamak discharge operation was obtained in current tokamaks, the effects of nitrogen seeding on plasma-facing components, especially the divertor target material (e.g. tungsten), have not been fully tested in a fusion-relevant steady-state linear plasma system with a high plasma density and plasma heat flux, in which deuterium and nitrogen mixed-gas discharge plasmas are irradiated onto a tungsten target, closely similar to the boundary region in a magnetic fusion configuration. This study addressed such a detailed irradiation, using a variety of surface analyses. Surface-temperature-sensitive tungsten nitride formation was determined, thus elucidating the interesting surface morphology of whisker, loop, and/or hook-like nanostructures in some surface temperature bands. The surface characteristics were determined using several kinds of surface analysis methods, including x-ray diffraction, energy dispersive x-ray analysis, nanoindentation, Raman spectroscopy, and spectrometry. The possibility of tungsten contamination into facing plasmas is discussed in terms of tungsten nitride melting. The relation to industrial applications of tungsten nitride has also been mentioned.