Path Integral Monte Carlo Simulations of Dense Plasma

了解材料在温暖稠密物质（WDM）和稠密等离子体状态下的理论特性是关键能源技术发展的核心目标，如先进的核反应堆和惯性约束聚变，冲击物理学，等离子体科学和库存管理。 该项目开发了一种创新的新技术，首次模拟第二排材料元件的稠密等离子体。该项目将利用Blue沃茨领导系统将这一新技术应用于一些关键材料，以便为冲击波实验提供指导，并为其他理论方法建立基准。该项目建议在温度-密度点网格上模拟一组材料，以推导等离子体条件下和WDM制度下的状态方程（EOS）。该项目的结果将对国家点火装置（NIF）和其他高能密度物理装置的设计人员具有不可估量的重要性。学生将广泛参与该项目，该项目推进了NSF的使命，以支持可能对国家做出贡献的基础研究。为了研究WDM机制，该项目将联合收割机与标准的Kohn-Sham密度泛函分子动力学（KS-DFMD）模拟相结合，后者在较低温度下更有效。虽然KS-DFMD已被用于精确预测温度高达100，000 K的许多固体和液体的结构，但它不适用于更高的温度，因为部分占据的电子轨道的数量达到难以控制的大数字。另一种方法，轨道自由密度泛函分子动力学（OF-DFMD）产生不准确的EOS结果，因为没有现有的自由能功能已经开发。能源部（DOE）国家实验室的合作者将使用PIMC EOS数据作为与现有半经验EOS生成方案的比较，并作为连续辐射流体动力学模拟的输入。该项目旨在建立一个有效的管道，从PIMC材料响应的宏观连续研究。一个重点将放在基准等离子体的重元素在非常高的温度（~100 eV）和低密度时产生的黑腔辐射加热烧蚀材料在间接驱动激光实验的方法。

Understanding the theoretical properties of materials in the warm dense matter (WDM) and dense plasma regimes is a central goal in the development of key energy technologies, such as advanced nuclear reactors and inertial confined fusion, shock physics, plasma science, and stockpile stewardship. The project has developed an innovative new technique to simulate dense plasmas of second-row material elements for the first time. The project will use the Blue Waters leadership system to apply this new technique to a number of key materials in order to provide guidance to shock wave experiments and establish benchmarks for other theoretical approaches. The project proposes to simulate a set of materials on a grid of temperature-density points in order to derive the equation of state (EOS) under plasma conditions and in the regime of WDM. Results from this project will be of immeasurable importance to the designers at the National Ignition Facility (NIF) and at other high-energy-density-physics facilities. Students will be extensively involved with the project, which advances the NSF mission to support basic research that may contribute to the nation?s prosperity.To study the WDM regime, the project will combine a novel PIMC simulations with standard, Kohn-Sham density functional molecular dynamics (KS-DFMD) simulations, which are more efficient at lower temperatures. While KS-DFMD has been used to accurately predict the structure of many solids and liquids up to temperatures on the order of 100,000 K, it is not applicable at much higher temperaturesbecause the number of partially occupied electronic orbitals reaches intractably large numbers. The alternate method, orbital-free density functional molecular dynamics (OF-DFMD) yields inaccurate EOS results because no existing free energy functional has been developed. Collaborators at Department of Energy (DOE) national labs will use the PIMC EOS data both as comparisons to existing semi-empirical, EOS-generating schemes, and as inputs for continuum radiation hydrodynamics simulations. The project aims to establish an efficient pipeline from PIMC to macroscopic continuum studies of materials response. An emphasis will be placed on benchmarking such methods for plasmas of heavy elements at very high temperatures (~100 eV) and low densities that are generated when Hohlraum radiation heats the ablator material in indirect drive laser experiments.