Dissipation and Kinetic Physics of Astrophysical Turbulence

天体物理湍流的耗散和运动物理学

• 批准号: 1614664
• 负责人: Vadim Roytershteyn
• 金额: $ 1.2万
• 依托单位: SPACE SCIENCE INSTITUTE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1614664&HistoricalAwards=false
• 关键词: Dissipation; Kinetic; Physics; Astrophysical; Turbulence

Turbulence is one of the fundamental physical phenomena associated with fluids, gasses, and plasmas. In astrophysical phenomena, turbulence provides a mechanism of efficient energy, momentum, and particle transport thus playing a key role in the dynamics of astrophysical objects. The solar wind has served as a unique laboratory for studies of turbulence due to the availability of measurements from spacecraft. Accordingly, considerable effort has been made to study solar wind turbulence using a combination of observational, theoretical, and computational tools. While understanding of the basic physics of this phenomenon has advanced greatly, a significant number of key questions remain unanswered. This project proposes to use the Blue Waters leadership class computing system to execute ground-breaking large scale simulations to investigate how energy cascades and is ultimately dissipated in the solar wind. This study will significantly advance the state of knowledge of turbulence and will represent a very important milestone in the efforts to perform realistic modeling of solar wind turbulence. Additionally, the project results will be of great interest to a wide community of researchers working on solar wind plasma, coronal plasma, and plasma astrophysics. Overall, this project is part of a larger stream of fundamental scientific research, which is central to the mission of the NSF.One particularly challenging question, which is the focus of this proposal, is what happens to the energy that is cascaded to kinetic scales by magnetohydrodynamic (MHD) turbulence. This question is not only of basic plasma physics interest, but is also directly related to the very important problem of solar wind and solar corona heating that is crucial to understanding of the Sun-Earth interaction, but has so far eluded a conclusive solution. This study will overcome many of the limitations of existing approaches and will provide complementary information covering effects and parameter regimes inaccessible to other techniques. The planned 3D simulations on Blue Waters will reach into the MHD scales while retaining kinetic effects and will provide a glimpse into many of the crucial questions posed by the research community. Additionally, the simulations will enable detailed comparison with spacecraft observations and exploration of the role of competing processes that are simultaneously present in the simulations. The wealth of information in these simulations is akin to data collected from many spacecraft missions and warrants analysis from the community at large. As such, the simulation data resulting from the project will be made available to the community for analysis.

湍流是与流体、气体和等离子体相关的基本物理现象之一。 在天体物理现象中，湍流提供了有效的能量、动量和粒子传输的机制，因此在天体物理物体的动力学中发挥着关键作用。由于航天器可以进行测量，太阳风已成为研究湍流的独特实验室。 因此，人们付出了相当大的努力来结合观测、理论和计算工具来研究太阳风湍流。虽然对这种现象的基本物理原理的理解已经取得了很大进展，但仍有大量关键问题尚未得到解答。该项目建议使用 Blue Waters 领先级计算系统来执行突破性的大规模模拟，以研究能量如何级联并最终在太阳风中消散。这项研究将显着提高对湍流的认识，并将成为对太阳风湍流进行真实建模的努力中的一个非常重要的里程碑。此外，该项目的结果将引起从事太阳风等离子体、日冕等离子体和等离子体天体物理学研究的广大研究人员的极大兴趣。总体而言，该项目是更广泛的基础科学研究的一部分，这是美国国家科学基金会使命的核心。一个特别具有挑战性的问题，也是该提案的重点，是级联到动能尺度的能量会发生什么通过磁流体动力学 (MHD) 湍流。这个问题不仅涉及基本的等离子体物理学兴趣，而且还与太阳风和日冕加热的非常重要的问题直接相关，这对于理解日地相互作用至关重要，但迄今为止尚未找到结论性的解决方案。 这项研究将克服现有方法的许多局限性，并将提供涵盖其他技术无法获得的效应和参数机制的补充信息。计划在 Blue Waters 上进行的 3D 模拟将达到 MHD 尺度，同时保留动力学效应，并将让我们了解研究界提出的许多关键问题。 此外，模拟还将能够与航天器观测进行详细比较，并探索模拟中同时存在的竞争过程的作用。这些模拟中的大量信息类似于从许多航天器任务中收集的数据，并且值得整个社区进行分析。因此，该项目产生的模拟数据将提供给社区进行分析。