Measuring the plasma composition in tokamaks with metallic plasma-facing components
Measuring the plasma composition in tokamaks with metallic plasma-facing components
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DOI：
10.1017/s0022377819000618
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发表时间：
2019-10
影响因子：
2.5
通讯作者：
M. Sertoli;P. Carvalho;C. Giroud;S. Menmuir;J. Contributors
中科院分区：
文献类型：
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作者：
M. Sertoli;P. Carvalho;C. Giroud;S. Menmuir;J. Contributors
在当前和未来具有金属等离子体面组件（pfc）的磁约束聚变装置中，如JET-ILW和ITER，等离子体成分的计算必须考虑大范围质量和电荷的多种杂质，解决它们的极向不对称性，并考虑不同元素的不同中心峰值。辐射和有效电荷的单一测量不足以表征这一复杂系统，需要对来自多种诊断的数据进行自一致的分析。这篇文章描述了一种同时计算等离子体成分的方法，该方法考虑了多达两个低z杂质和两个中/高z杂质的贡献。该分析源自Sertoli et al. （Rev. Sci.）中解释的方法。Instrum。， vol. 89(11), 2018, 113501)，扩展到包括更多的杂质，并在同一框架内连贯地分析多个诊断。本文报道的Ne- ilw混合放电实例表明，Be、Ne、Ni和W是同时解释软x射线发射、被动真空紫外光谱测量的W浓度、有效电荷的视距综合测量、软x射线（SXR）发射的极向不对称性所必需的。用电荷交换复合光谱法测得的Ne密度和用测热法测得的总辐射的视距积分。这种一致的元素组成图使计算有效电荷、稀释和总辐射的径向分布成为可能。对于迄今为止分析的案例，这些通常与目前在模拟JET-ILW排放时使用的典型假设有很大不同。这将影响中子率、电流密度分布和热输运的计算。这些考虑当然适用于所有现在和未来的磁控聚变装置，这些装置展示了多材料等离子体面组件，包括ITER。
In present and future magnetic confined fusion devices with metallic plasma-facing components (PFCs) such as JET-ILW and ITER, the calculation of the plasma composition must account for multiple impurities of a wide range of mass and charge, resolve their poloidal asymmetries and account for different central peakings for various elements. Single measurements of radiation and effective charge are not enough to characterize this complex system and a self-consistent analysis of data from multiple diagnostics is required. This contribution describes a method to calculate the plasma composition simultaneously accounting for contributions of up to two low-Z impurities, and two mid-/high-Z impurities. The analysis stems from methodologies explained in Sertoli et al. (Rev. Sci. Instrum., vol. 89 (11), 2018, 113501), expanded to include more impurities and to coherently analyse multiple diagnostics within the same framework. The example Ne-seeded JET-ILW hybrid discharge reported here shows that Be, Ne, Ni and W are necessary to simultaneously explain the observed soft X-ray emission, the W concentration measured by passive vacuum ultra-violet spectroscopy, the line-of-sight integrated measurement of the effective charge, the observed poloidal asymmetry of the soft X-ray (SXR) emission, the Ne density measured by charge-exchange-recombination spectroscopy and the line-of-sight integrals of the total radiation as measured by bolometry. This consistent picture of the elemental composition enables the calculation of the radial profiles of the effective charge, the dilution and total radiation. For the cases analysed up to now, these are often very different from the typical assumptions presently used when modelling JET-ILW discharges. This will affect, among others, the calculation of neutron rates, current density profile and heat transport. These considerations are of course valid for all present and future magnetic-controlled fusion devices which exhibit multi-material plasma-facing components, including ITER.