Kwak Jong-Gu, Wang Son Jong, Kim Sun Ho, Park Jae Min, Na Hoon Kyun
Korea Atomic Energy Research Institute, 1045 Daedeok-daero, Yuseong, Daejeon, South Korea, 305-353.
Rev Sci Instrum. 2010 Oct;81(10):10E510. doi: 10.1063/1.3478560.
The control of the ratio of hydrogen to the deuterium is one of the very important issues for ion cyclotron range of frequency (ICRF) minority heating as well as the plasma wall interaction in the tokamak. The ratio of hydrogen to deuterium during the tokamak shot was deduced from the emission spectroscopy measurements during the KSTAR 2009 experimental campaign. Graphite tiles were used for the plasma facing components (PFCs) at KSTAR and its surface area exposed to the plasma was about 11 m(2). The data showed that it remained as high as around 50% during the campaign period because graphite tiles were exposed to the air for about two months and the hydrogen contents at the tiles are not fully pumped out due to the lack of baking on the PFC in the 2009 campaign. The validation of the spectroscopy method was checked by using the Zeeman effects and the ratio of hydrogen to the deuterium is compared with results from the residual gas analysis. During the tokamak shot, the ratio is low below 10% initially and saturated after around 1 s. When there is a hydrogen injection to the vessel via ion cyclotron wall conditioning and the boronization process where the carbone is used, the ratio of the hydrogen to the deuterium is increased by up to 100% and it recovers to around 50% after one day of operation. However it does not decrease below 50% at the end of the experimental campaign. It was found that the full baking on the PFC (with a high temperature and sufficient vacuum pumping) is required for the ratio control which guarantees the efficient ICRF heating at the KSTAR 2010 experimental campaign.
氢与氘的比例控制是托卡马克中离子回旋频率范围（ICRF）少数粒子加热以及等离子体与壁相互作用的非常重要的问题之一。在KSTAR 2009实验期间，通过发射光谱测量推导出了托卡马克放电期间氢与氘的比例。KSTAR使用石墨瓦作为面向等离子体的部件（PFC），其暴露于等离子体的表面积约为11平方米。数据表明，在实验期间该比例一直高达约50%，这是因为石墨瓦暴露在空气中约两个月，并且由于2009年实验中PFC缺乏烘烤，瓦片中的氢含量没有被完全抽出。通过利用塞曼效应检查了光谱法的有效性，并将氢与氘的比例与残余气体分析的结果进行了比较。在托卡马克放电期间，该比例最初低于10%，并在约1秒后饱和。当通过离子回旋壁调节和使用碳的硼化过程向容器中注入氢时，氢与氘的比例增加高达100%，并且在运行一天后恢复到约50%。然而，在实验结束时它不会降至50%以下。研究发现，为了控制该比例，需要对PFC进行充分烘烤（高温并充分抽真空），这能确保在KSTAR 2010实验期间实现高效的ICRF加热。
