Cross-code comparison of the impact of the fill tube on high yield implosions on the National Ignition Facility
Cross-code comparison of the impact of the fill tube on high yield implosions on the National Ignition Facility
复制标题
填充管对国家点火装置高当量内爆影响的跨代码比较
作者：
B. Haines;D. Clark;C. Weber;M. Edwards;S. Batha;J. Kline
填充管用于将氘和氚燃料注入安装在国家点火装置上的惯性约束聚变舱。这些填充管已被证明对胶囊性能具有不利影响，主要是通过将低密度路径引入到中心燃料区域中，使得烧蚀材料能够喷射到热点中。由于与填充管相关联的高度非线性流的复杂性以及在内爆实验中诊断填充管射流的演化的挑战，这种扰动源如何演化的不确定性很大。在这里，我们报告的结果进行了详细的代码比较，以了解不确定性的计算建模填充管的内爆性能的影响。这项研究采用了两个辐射流体动力学代码，HYPENS和XPENS，采用非常不同的网格划分策略和流体动力学求解器，以及两个辐射传输方法，离散纵坐标和多组扩散。我们的研究结果表明，一般良好的协议之间的代码通过大多数的内爆，虽然他们表示不透明度平均方法的敏感性。在内爆后期，污染物的分布和数量出现差异，尽管这些差异对由于填充管而导致的产量减少的量具有非常小的影响。虽然这些结果证明了填充管建模对算法选择的敏感性，但由于填充管几何结构的预期变化，相对于已知灵敏度，观察到的代码之间的差异较小。最后，我们已经开发出一种方法进行多组扩散模拟，表现出良好的协议，更准确的离散纵坐标方法。
Fill tubes are used to inject deuterium and tritium fuel into inertial confinement fusion capsules fielded on the National Ignition Facility. These fill tubes have been shown to have a detrimental effect on capsule performance, primarily by introducing a low-density pathway into the central fuel region that enables the jetting of ablation material into the hot spot. Due to the complexity of the highly nonlinear flow associated with the fill tube and the challenge of diagnosing the evolution of the fill tube jet late in the implosion experiments, the uncertainty in how this perturbation source evolves is great. Here, we report on the results of a detailed code comparison performed to understand uncertainties in computational modeling of the impact of fill tubes on implosion performance. The study employed two radiation-hydrodynamics codes, HYDRA and xRAGE, which employ very different meshing strategies and hydrodynamics solvers, as well as two radiation transport methodologies, discrete ordinates and multi-group diffusion. Our results demonstrate generally good agreement between codes through most of the implosion although they indicate sensitivity to opacity averaging methods. Late in the implosion, differences arise in the distribution and amount of contaminant although these differences have a remarkably small impact on the amount of yield reduction due to the fill tube. While these results demonstrate sensitivity in fill tube modeling to algorithmic choices, the observed differences between codes are small relative to known sensitivities due to expected variations in the fill tube geometry. Finally, we have developed a methodology for performing multi-group diffusion simulations that show good agreement with the more accurate discrete ordinates method.
惯性约束聚变内爆中性能退化扰动的诊断特征
影响因子：
2.2
作者：
McGlinchey K
通讯作者：
McGlinchey K