Collaborative Research: Simulating Two-Fluid MHD Turbulence in Star Forming Molecular Clouds on the Blue Waters System

合作研究：模拟 Blue Waters 系统上恒星形成分子云中的两流体 MHD 湍流

• 批准号: 1713782
• 负责人: Alexandre Lazarian
• 金额: $ 2万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1713782&HistoricalAwards=false
• 关键词: Collaborative; Research; Simulating; Two; Fluid

Astrophysics is at the threshold of a new data-rich and simulation-rich era in star-formation studies. The question of how stars form is fascinating in itself and has a great impact on several other areas of astrophysics. There is a general consensus that a predominant amount of star formation in our Galaxy takes place in molecular clouds, and specifically in giant molecular clouds (GMC). Consequently, NASA has made multi-million dollar investments in instruments such as HAWC+ on the SOFIA airborne observatory with the specific goal of understanding the turbulent nature of star forming clouds. This project on Blue Waters will use the petascale capabilities of the system to validate theories of star formation by simulating the same processes the NASA's instruments are currently measuring.This project will carry out simulations on Blue Waters that integrate the ions and the neutrals to reproduce the turbulent, partially ionized gas in which stars form. Since neutral gas does not couple to the magnetic field, but ionized gas do, the project has built frontline simulation capabilities for simulating two-fluid plasmas. Simultaneously, the project has built theoretical and numerical analysis tools that will enable cross-comparison of simulations with observations. This cross-comparison provides important verification of theories of star formation. Further diagnostics that emerge from the simulations will also be used to motivate more detailed observations. In this fashion, Blue Waters will enable theory, computation and detailed observations to support one another. In addition, the project intends to combine education in computational astrophysics with code releases of their simulation tools to the greater astrophysics community.

天体物理学正处于恒星形成研究中一个新的数据丰富和模拟丰富的时代的门槛。恒星如何形成的问题本身就很吸引人，对天体物理学的其他几个领域也有很大的影响。有一个普遍的共识，即在我们的银河系中，星星的形成主要发生在分子云中，特别是在巨大的分子云（GMC）中。因此，美国宇航局已经在索菲亚空中天文台的HAWC+等仪器上投资了数百万美元，其具体目标是了解星星形成云的湍流性质。蓝色沃茨上的这个项目将利用该系统的千万亿次能力，通过模拟美国宇航局的仪器目前正在测量的相同过程来验证星星形成的理论。这个项目将在蓝色沃茨上进行模拟，将离子和中性粒子结合起来，再现恒星形成时湍流的、部分电离的气体。 由于中性气体不与磁场耦合，但电离气体与磁场耦合，因此该项目已经建立了模拟双流体等离子体的前沿模拟能力。同时，该项目还建立了理论和数值分析工具，将模拟与观测进行交叉比较。这种交叉比较为星星形成理论提供了重要的验证。模拟中出现的进一步诊断也将用于激发更详细的观察。通过这种方式，Blue沃茨将使理论、计算和详细的观察相互支持。 此外，该项目打算将计算天体物理学的联合收割机教育与向更大的天体物理学界发布其模拟工具的代码相结合。

项目成果

Distribution of Velocity Gradient Orientations: Mapping Magnetization with the Velocity Gradient Technique

• DOI: 10.3847/1538-4357/aad7ff
• 发表时间: 2018-02
• 期刊: The Astrophysical Journal
• 作者: A. Lazarian;K. Yuen;K. Ho;Jun-De Chen;Victor Lazarian;Zekun Lu;Zekun Lu;Bo Yang;Yue Hu;Yue Hu

Mapping of the Structure of the Galactic Magnetic Field with Velocity Gradients: Test Using Star Light Polarization

• DOI: 10.3847/1538-4357/ab0552
• 发表时间: 2018-05
• 期刊: The Astrophysical Journal
• 作者: Diego F. González-Casanova;A. Lazarian