The occurrence and damage of unipolar arcing on fuzzy tungsten
The occurrence and damage of unipolar arcing on fuzzy tungsten
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模糊钨丝单极飞弧的发生及损坏
DOI：
10.1016/j.jnucmat.2014.09.009
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发表时间：
2015
影响因子：
3.1
通讯作者：
N. L. Cardozo
中科院分区：
文献类型：
--
作者：
D. Aussems;D. Nishijima;C. Brandt;H. V. D. Meiden;M. Vilémová;J. Matějíček;G. D. Temmerman;R. Doerner;N. L. Cardozo
本研究调查了聚变反应堆偏滤器中的单极电弧是否是偏滤器磨损加剧的潜在原因。发现1 μm的纳米绒毛生长就足以引发电弧，这主要取决于鞘层电位降和电子密度。由电弧引起的平均质量损失率由质量损失测量确定，并发现与从电弧电流估计的值一致。平均电弧轨道侵蚀深度估计使用测得的质量损失和损坏的表面积，被发现是十分之一的模糊层厚度。由于模糊结构的熔化，实际深度更大，并且一些电弧轨迹偶尔出现，甚至到达模糊层之外的本体。因此，本研究的结论是，未来托卡马克（如ITER）的偏滤器中的电弧可能是表面损伤和等离子体污染的重要原因。
This research investigated whether unipolar arcing in the divertor of fusion reactors is a potential cause for enhanced wear of the divertor. It was found that 1 μm of nano-fuzz growth is sufficient to initiate arcing, mainly depending on the sheath potential drop and electron density. The average mass loss rate induced by the arc was determined from mass loss measurements and found to be consistent with the value estimated from the arc current. The average arc track erosion depth was estimated by using the measured mass loss and damaged surface area and was found to be one tenth of the fuzzy layer thickness. Due to melting of the fuzzy structures the actual depth is larger and some arc tracks occasionally appeared to even reach the bulk beyond the fuzzy layer. The conclusion of this study is therefore that arcing in the divertor of future tokamaks (e.g. ITER) potentially is an important cause for surface damage and plasma pollution.