INSPIRE: Adaptive Multi-Scale Modeling of Plasmas

INSPIRE：等离子体的自适应多尺度建模

• 批准号: 1513379
• 负责人: Gabor Toth
• 金额: $ 100万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1513379&HistoricalAwards=false
• 关键词: INSPIRE; Adaptive; Multi; Scale; Modeling

This INSPIRE project is jointly funded by the Plasma Physics and Computational Physics programs in the Physics Division in the Mathematical and Physical Sciences Directorate, the Magnetospheric Physics program in the Atmospheric and Geospace Sciences Division in the Directorate for Geosciences, and the Office of Integrative Activities. Ionized gas, or in scientific terms plasma, is the most common state of matter in the Universe. In the solar system, for example, the solar corona where solar eruptions occur, the solar wind that carries the erupted plasma and magnetic field from the Sun to the Earth, the magnetosphere surrounding the Earth and protecting us from the harmful effects of the eruption, and the ionosphere through which radio communications and GPS signals propagate and get disturbed, all consist of plasma. Understanding plasma is crucial for predicting and mitigating the effects of space weather. Plasmas also play an important role in engineering, for example in the design of fusion type reactors that promise to provide an inexhaustible source of clean energy for humanity. Computational modeling of plasma dynamics is very challenging due to the different spatial and temporal scales and the complex behavior of the system. The project is aimed at improving the efficiency of present plasma simulation models by a factor of 1000 or even more. If successful, the new model will provide accurate and affordable simulations for systems that currently cannot be modeled even on the largest supercomputers.There are different approaches for plasma modeling that all have advantages and drawbacks. The most accurate kinetic methods describe all the important effects of plasma by describing the full distribution function in a six dimensional phase space, but they have tremendous computational cost. Even on today's supercomputers, modeling a large three-dimensional system with kinetic methods is far out of reach. Alternative fluid-type methods describe the plasma distribution function with a handful of moments, such as density, velocity and pressure. Solving for these quantities in addition to the magnetic field can be done quite efficiently, and in fact one can model the solar corona, the solar wind, and the magnetosphere with global fluid models with reasonable computational resources. Unfortunately, in most systems there are some parts of the domain where the fluid description is not sufficient, and this can have consequences for the global solution. The project aims at combining the kinetic and fluid type methods in an adaptive and dynamic fashion. The expensive kinetic model will be restricted to the small parts of the domain where the fluid description is not accurate enough, while the efficient fluid methods will be employed in the vast majority of the domain. This hybrid approach promises to provide accurate solutions at a tiny fraction of the cost of the fully kinetic models. A speed up of factor of 1000 or even more is expected. This will allow modeling global plasma systems with unprecedented accuracy and vastly improve our understanding and predictive capabilities.

该激发项目由数学和物理科学局的物理部门的等离子物理和计算物理计划共同资助。 离子气体或科学术语血浆是宇宙中最常见的物质状态。例如，在太阳能系统中，发生太阳爆发的太阳能电晕，带有爆发的血浆和磁场从太阳到地球的太阳能，围绕地球的磁层，保护我们免受喷发的有害影响，以及电线层的有害效果，而无线电通信和GPS信号传播并均受到Plassma的影响。了解血浆对于预测和减轻太空天气的影响至关重要。等离子体在工程中也起着重要的作用，例如在融合类型反应堆的设计中，有望为人类提供无穷无尽的清洁能源来源。由于不同的空间和时间尺度以及系统的复杂行为，血浆动力学的计算建模非常具有挑战性。该项目旨在提高当前等离子体模拟模型的效率1000倍甚至更多。如果成功，新模型将为即使在最大的超级计算机上也无法建模的系统提供准确且负担得起的模拟。等离子体建模的方法都有不同的方法，这些方法都具有优势和缺点。最准确的动力学方法通过描述六维相空间中的完整分布函数来描述血浆的所有重要效果，但它们具有巨大的计算成本。即使在当今的超级计算机上，用动力学方法对大型三维系统进行建模也是遥不可及的。替代流体型方法描述了血浆分布函数，并用少数矩，例如密度，速度和压力。除了磁场外，可以非常有效地解决这些数量，实际上，可以使用合理的计算资源对太阳能电晕，太阳能风和磁层进行建模。不幸的是，在大多数系统中，域的某些部分在其中流体描述不够，这可能会对全球解决方案产生后果。该项目旨在以自适应和动态的方式组合动力学和流体类型方法。昂贵的动力学模型将仅限于域的小部分，那里的流体描述不够准确，而有效的流体方法将用于绝大多数域中。这种混合方法有望以完全动力学模型的一小部分提供准确的解决方案。预计将增加1000倍甚至更高的速度。这将允许以前所未有的准确性对全球等离子体系统进行建模，并大大提高我们的理解和预测能力。

项目成果

A six-moment multi-fluid plasma model

六时刻多流体等离子体模型

• DOI: 10.1016/j.jcp.2019.02.023
• 发表时间: 2019
• 期刊: Journal of Computational Physics
• 影响因子: 4.1
• 作者: Huang, Zhenguang;Tóth, Gábor;van der Holst, Bart;Chen, Yuxi;Gombosi, Tamas
• 通讯作者: Gombosi, Tamas

Gauss's Law satisfying Energy-Conserving Semi-Implicit Particle-in-Cell method

• DOI: 10.1016/j.jcp.2019.02.032
• 发表时间: 2018-08
• 期刊: J. Comput. Phys.
• 作者: Yuxi Chen;G. Tóth

Scaling the Ion Inertial Length and Its Implications for Modeling Reconnection in Global Simulations: SCALING THE ION INERTIAL LENGTH

缩放离子惯性长度及其对全局模拟中重连接建模的影响：缩放离子惯性长度

• DOI: 10.1002/2017ja024189
• 发表时间: 2017
• 期刊: Journal of Geophysical Research: Space Physics
• 作者: Tóth, Gábor;Chen, Yuxi;Gombosi, Tamas I.;Cassak, Paul;Markidis, Stefano;Peng, Ivy Bo
• 通讯作者: Peng, Ivy Bo