During the operation of nuclear fusion reactors, plasma-facing components lining the reactor vessel are continually bombarded by plasma species. The penetration and subsequent trapping of these bombarding plasma ions has implications for component damage as well as in-vessel inventory. Accurately predicting the expected ion penetration depth profiles at a range of plasma ion and surface temperatures typical of fusion reactor operating conditions will inform the scrape-off layer design to limit particle radiation damage and tritium trapping in order to prolong the lifetime of the plasma-facing components and satisfy the DT fuel cycle requirements. By defining a statistical distribution for ion penetration depth and describing the evolution of its parameters across the fusion parameter space of interest, the expected ion deposition depth profiles can be calculated for any subset of ion and surface temperature ranges as needed. Molecular dynamics simulations were used to study the bombardment of beryllium lattices with surface temperatures of up to 1100 K by 5 eV–150 eV deuterium and tritium ions, and the resulting ion penetration depths were investigated. The distributions of two penetration depth quantities, considered from the perspectives of lattice damage and hydrogen retention are defined and their distribution parameter dependence on surface and ion temperature is identified. The expected positive correlation between penetration depth and ion temperature is observed, where the non-linear relationship between these quantities indicates the expected form of the velocity dependence of nuclear stopping power at low bombardment energies. Isotope effects on the distributions are also investigated, with results suggesting that heavier ions have comparably lower mobility within the sample and will generally accumulate closer to the surface. A short study on ion deposition rates is also performed; a non-linear increase of deposition rate with increasing bombarding ion energy has been observed, and evidence of a weak positive surface temperature correlation has been noted.

中文翻译：

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通过分子动力学模拟研究面向铍等离子体的组件中氢物质的穿透深度分布

在核聚变反应堆运行期间，反应堆容器内衬的面向等离子体的部件不断受到等离子体物质的轰击。这些轰击等离子体离子的穿透和随后的捕获会对部件损坏以及容器内库存产生影响。准确预测聚变反应堆典型运行条件下的一系列等离子体离子和表面温度下的预期离子穿透深度剖面，将为刮除层设计提供信息，以限制粒子辐射损伤和氚捕获，从而延长面向等离子体的寿命组件并满足DT燃料循环要求。通过定义离子穿透深度的统计分布并描述其参数在感兴趣的聚变参数空间中的演变，可以根据需要计算离子和表面温度范围的任何子集的预期离子沉积深度分布。采用分子动力学模拟研究了 5 eV-150 eV 氘和氚离子轰击表面温度高达 1100 K 的铍晶格，并研究了由此产生的离子穿透深度。从晶格损伤和氢保留的角度考虑，定义了两个穿透深度量的分布，并确定了它们的分布参数对表面和离子温度的依赖性。观察到穿透深度和离子温度之间的预期正相关性，其中这些量之间的非线性关系表明低轰击能量下核阻止功率的速度依赖性的预期形式。还研究了同位素对分布的影响，结果表明较重的离子在样品内具有相对较低的迁移率，并且通常会聚集在更靠近表面的位置。还对离子沉积速率进行了简短的研究；已经观察到沉积速率随着轰击离子能量的增加而非线性增加，并且已经注意到表面温度存在弱正相关性的证据。