Investigations into penetration depth profiles of hydrogenic species in beryllium plasma-facing components via molecular dynamics simulations
Investigations into penetration depth profiles of hydrogenic species in beryllium plasma-facing components via molecular dynamics simulations
复制标题
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
DOI：
10.1088/1361-6587/ad20f9
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发表时间：
2024
影响因子：
2.2
通讯作者：
Liptak A
中科院分区：
文献类型：
--
作者：
Liptak A
在核聚变反应堆的操作期间，内衬反应堆容器的面向等离子体的部件被等离子体物质持续轰击。这些轰击等离子体离子的穿透和随后的捕获对组件损坏以及容器内库存具有影响。在聚变反应堆运行条件的典型等离子体离子和表面温度范围内，准确预测预期的离子穿透深度分布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部件的寿命并满足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上的演变，可以根据需要为离子和表面温度范围的任何子集计算预期的离子沉积深度分布。采用分子动力学模拟方法研究了5 eV ~ 150 eV的氘和氚离子轰击温度高达1100 K的铍晶格，并对离子的穿透深度进行了研究。定义了从晶格损伤和氢保留的角度考虑的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。穿透深度和离子温度之间的预期的正相关性被观察到，这些量之间的非线性关系表明在低轰击能量的核阻止本领的速度依赖性的预期形式。同位素对分布的影响也进行了研究，结果表明，较重的离子具有较低的流动性内的样品，一般会积累更接近表面。离子沉积速率的一个简短的研究也进行了;已观察到的沉积速率随轰击离子能量的增加非线性增加，并已注意到一个弱的正表面温度相关性的证据。
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.