CAREER: Continuum Kinetic Studies of Hydrodynamic and Magneto Hydrodynamic Instabilities

对星星死亡时发生的超新星爆炸的观测和记录已经有几千年了。这样的观测激发了实验室实验来复制天体物理现象。与此同时，已经发展了计算建模能力，目的是从观察和实验中再现结果。该项目的目标是最终解决与天体物理学相关的数值模拟和真实的世界测量之间的现有差异。作为本研究的一部分，开发的新型数值工具将广泛适用于基础科学问题，国家安全，能源和航天器工程。 强有力的整合教育计划将通过在线用户体验，让K-12学生通过研究生院参与科学，技术，工程和数学（STEM）的研究和职业机会。教育和外展活动还将努力鼓励妇女和代表性不足的群体通过与弗吉尼亚理工大学工程多样性增强中心和弗吉尼亚州少数民族服务社区学院的合作追求STEM职业。在高能量密度制度下，数值模拟已经无法重现几十年来的实验和观察结果。高能量密度天体物理和实验室等离子体的最新数值模拟使用流体模型，特别是辐射流体动力学和辐射磁流体动力学模型。这些单流体模型中的显著缺陷包括无法捕获更先进的高保真多流体模型中所包括的物理效应。 缺失的物理学可以显著地影响等离子体传输，其可以具有显著的各向异性。此外，即使是最先进的流体模型也可能忽略非热粒子群对等离子体传输的影响。匹配实验数据的关键是在流体模拟中包括特设的可调参数。什么是必要的，但一直是不切实际的，直到最近由于计算的限制，是第一原理高维动力学计算，可以解决决定性的实验和流体动力学代码之间的差异是否可以解释使用动力学物理。本研究将包括第一原理动力学计算，使用一种新的，连续动力学，高阶精度，计算效率高的算法来研究等离子体动力学和运输的存在下，在高能量密度等离子体的流体动力学和磁流体动力学不稳定性。该项目将解决高能量密度实验和模拟之间长期存在的差异，因此，可以大大提高我们对等离子体传输的理解，并在许多研究领域产生影响。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Observations of supernovae explosions that occur upon the death of a star have been made and documented for thousands of years. Such observations have motivated laboratory experiments to replicate astrophysical phenomena. Concurrently, there has been development of computational modeling capabilities aimed at reproducing results from both observations and experiments. The goal of this project is to conclusively address the existing discrepancies between numerical simulations and real world measurements in regimes of relevance to astrophysics. Novel numerical tools to be developed as part of this study will have broad applicability to fundamental science questions, national security, energy, and spacecraft engineering. The strongly integrated education plan will engage students from K-12 through graduate school in research and career opportunities in science, technology, engineering, and mathematics (STEM) through an online user experience. The education and outreach activities will also strive to encourage women and under-represented groups to pursue STEM careers through collaborations with the Center for the Enhancement of Engineering Diversity at Virginia Tech and minority-serving community colleges in Virginia.In high-energy-density regimes, numerical simulations have been unable to reproduce the results from experiments and observations for decades. The state-of-the-art in numerical simulations of high-energy-density astrophysical and laboratory plasmas uses fluid models, specifically radiation-hydrodynamic and radiation-magnetohydrodynamic models. Significant deficiencies in these single-fluid models include the inability to capture physics effects included in more advanced high-fidelity multi-fluid models. The missing physics can notably impact plasma transport, which may have significant anisotropies. Furthermore, the effect of non-thermal particle population on plasma transport may be missed even by most advanced fluid models. The key to matching experimental data has been to include ad hoc tunable parameters in fluid simulations. What is necessary, but has been impractical until recently due to computational limitations, are first-principles high-dimensional kinetic calculations that can address conclusively whether the discrepancies between experiments and hydrodynamic codes could be explained using kinetic physics. The present study will include first-principles kinetic calculations using a novel, continuum-kinetic, high-order accurate, and computationally efficient algorithm to study plasma dynamics and transport in the presence of hydrodynamic and magnetohydrodynamic instabilities in high-energy-density plasmas. This project will address long-standing discrepancies between high-energy-density experiments and simulations and, as a result, could significantly advance our understanding of plasma transport with implications in a number of research areas.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.