Dynamic Process of Hydrogen Recycling at First Wall

为了研究聚变反应堆第一壁的氢再循环行为，系统地研究了不同第一壁候选材料在氢离子和原子轰击下氢的反射、再发射和渗透的动态过程。对氢离子轰击下目标表面的可见光发射进行了光谱分析。采用氩离子激光器，对辐照表面的损伤过程进行了原位激光拉曼分析。所得结果总结如下：(1)发现靶表面反射氢原子发出的H辐射对于理解石墨和钼的氢反射非常有用。(2)观察到金属靶表面有宽带发射，其原因是表面有杂质氧。从陶瓷中观察到来自陶瓷色心或杂质的强光发射。排放的强度很大程度上取决于目标条件。在石墨靶带中，观察到CH和CH_2分子的发射，表明H-C相互作用。目前的结果清楚地表明，离子诱导光子（光）发射是研究离子-固体相互作用的新技术。(3)利用原位激光拉曼光谱对石墨表面氢离子轰击损伤过程进行了研究，成功地为氢离子轰击石墨的非晶化过程提供了清晰的图像。(4)利用氢分子、原子和离子考察了氢在第一壁候选材料上的再发射、滞留和渗透，对比分析了三种情况下离子轰击能量沉积对氢回收的影响。

In order to investigate hydrogen recycling behavior at first wall of fusion reactor, dynamic process of hydrogen reflection, re-emission and permeation under hydrogen ion and atom bombardments are systematically investigated for various first wall candidate materials. Visible light emission from the target surface under the hydrogen ion bombardment is also analyzed spectroscopically. Employing Ar ion laser, in-situ laser Raman analysis is carried out to monitor damaging process of the irradiated surface.Results obtained are summarized as follows(1) H emission emitted by reflected hydrogen atom from target surface is found to be very useful for understanding hydrogen reflection from graphite and molybdenum.(2) Broad band emission from the surface of metallic target is observed and is attributed to be due to the impurity oxygen on the surface. Strong light emission is observed from ceramics originating from the color centers or impurities of the ceramics. The intensity of the emission quite dependent on the target condition. In the case of graphite target band emission from CH and CH_2 molecules is observed indicating H-C interaction. The present results clearly indicate that the ion induced photon (light) emission is a new technique for investigation of ion-solid interactions.(3) Damaging process of the graphite surface by hydrogen ion bombardment are examined by the in-situ laser Raman spectroscopy, which is very successful giving clear image for amorphizing process of the graphite by hydrogen ion bombardment.(4) Hydrogen reemission, retention and permeation at the first wall candidate materials are investigated using hydrogen molecules, atoms and ions and the effect of energy deposition of ion bombardment on hydrogen recycling is analyzed comparing the three cases.