Hu S X, Bishel David T, Chin David A, Nilson Philip M, Karasiev Valentin V, Golovkin Igor E, Gu Ming, Hansen Stephanie B, Mihaylov Deyan I, Shaffer Nathaniel R, Zhang Shuai, Walton Timothy
Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY, 14623-1299, USA.
Department of Mechanical Engineering, University of Rochester, Rochester, NY, 14623, USA.
Nat Commun. 2022 Nov 16;13(1):6780. doi: 10.1038/s41467-022-34618-6.
Spectroscopic measurements of dense plasmas at billions of atmospheres provide tests to our fundamental understanding of how matter behaves at extreme conditions. Developing reliable atomic physics models at these conditions, benchmarked by experimental data, is crucial to an improved understanding of radiation transport in both stars and inertial fusion targets. However, detailed spectroscopic measurements at these conditions are rare, and traditional collisional-radiative equilibrium models, based on isolated-atom calculations and ad hoc continuum lowering models, have proved questionable at and beyond solid density. Here we report time-integrated and time-resolved x-ray spectroscopy measurements at several billion atmospheres using laser-driven implosions of Cu-doped targets. We use the imploding shell and its hot core at stagnation to probe the spectral changes of Cu-doped witness layer. These measurements indicate the necessity and viability of modeling dense plasmas with self-consistent methods like density-functional theory, which impact the accuracy of radiation transport simulations used to describe stellar evolution and the design of inertial fusion targets.
在数十亿个大气压下对稠密等离子体进行光谱测量，为我们对物质在极端条件下的行为的基本理解提供了检验。在这些条件下开发可靠的原子物理模型，并以实验数据为基准，对于更好地理解恒星和惯性聚变靶中的辐射输运至关重要。然而，在这些条件下进行详细的光谱测量很少见，并且基于孤立原子计算和特设连续谱降低模型的传统碰撞辐射平衡模型，在固体密度及以上时已被证明存在问题。在这里，我们报告了使用激光驱动掺杂铜靶的内爆，在数十亿个大气压下进行的时间积分和时间分辨X射线光谱测量。我们利用内爆壳及其停滞时的热芯来探测掺杂铜见证层的光谱变化。这些测量表明了用密度泛函理论等自洽方法对稠密等离子体进行建模的必要性和可行性，这会影响用于描述恒星演化和惯性聚变靶设计的辐射输运模拟的准确性。
