Modelling of local carbon deposition from methane and ethene injection through graphite and tungsten test limiters in TEXTOR
Modelling of local carbon deposition from methane and ethene injection through graphite and tungsten test limiters in TEXTOR
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DOI：
10.1088/0741-3335/52/4/045005
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发表时间：
2010-04
影响因子：
2.2
通讯作者：
R. Ding;A. Kirschner;D. Borodin;S. Brezinsek;A. Kreter;M. Tokar;J. Chen;O. Schmitz;V. Philipps;U. Samm;J. Li
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文献类型：
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作者：
R. Ding;A. Kirschner;D. Borodin;S. Brezinsek;A. Kreter;M. Tokar;J. Chen;O. Schmitz;V. Philipps;U. Samm;J. Li
利用三维蒙特卡罗代码ERO模拟了专门的TEXTOR实验，其中甲烷13CH4和乙烯13C2H4通过石墨和钨球形限制器注入等离子体，以研究局部碳的运输和沉积。利用光谱学跟踪观察到的烃裂解产物，并通过死后表面分析测量局部13C沉积效率。实验结果表明，13C沉积对衬底和气体的依赖性已被模拟。模型的主要不确定输入参数，如背景等离子体中的12C浓度、碳氢化合物的有效粘附系数和再沉积碳的增强侵蚀，已通过模型和实验之间的基准确定。在相同的参数下，模拟的13C沉积效率与实验结果吻合较好（0.8 ~ 2.1%）。此外，通过模拟可以很好地再现13C沉积在限制表面上的分布。石墨上13C的沉积量比钨限制器高，主要是由于碳在钨上的反射率更高，钨表面碳膜的物理溅射比石墨高。13C2H4的13C沉积量大于13CH4的沉积量，这可以解释为13C2H4的13C沉积量大于13CH4的13C沉积量，这主要是由不同的质量和反应速率系数决定的。
The 3D Monte Carlo code ERO has been used to simulate dedicated TEXTOR experiments in which methane 13CH4 and ethene 13C2H4 were injected into the plasma through graphite and tungsten spherical limiters to investigate local carbon transport and deposition. Spectroscopy was used to follow the observable hydrocarbon break-up products, and the local 13C deposition efficiency was measured by post-mortem surface analysis. The experimental observations showing the dependence of the 13C deposition on substrate and gas have been modelled. The main uncertain input parameters for the modelling, as 12C concentration in the background plasma, effective sticking coefficient for hydrocarbons and enhanced erosion of redeposited carbon, have been defined by benchmarking between modelling and experiment. With the same set of parameters, the modelled 13C deposition efficiencies are in good agreement with the experimental ones (0.8–2.1%). Also, the observed distribution of 13C deposition on the limiter surfaces is well reproduced by modelling. The higher amount of 13C deposition on graphite compared with tungsten limiter is mainly due to the higher reflection of carbon on tungsten and the higher physical sputtering of carbon film on top of the tungsten compared with graphite. The larger amount of 13C deposition for 13C2H4 instead of 13CH4 injection can be explained by more 13C returning to the limiter surface from 13C2H4 injection than 13CH4 injection, which is mainly determined by the different masses and reaction rate coefficients.