Nonlocal Magneto-Curvature Instabilities and their Associated Nonlinear Transport in Astrophysical Disks

天体物理盘中的非局域磁曲率不稳定性及其相关的非线性输运

• 批准号: 2308839
• 负责人: Fatima Ebrahimi
• 金额: $ 45.8万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-15 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2308839&HistoricalAwards=false
• 关键词: Nonlocal; Magneto; Curvature; Instabilities; their

This award supports a study of the physics of rotating magnetized plasmas observed in many astrophysical systems and laboratory experiments. New observational discoveries about black holes and accretion disks increasingly uncover that our universe is immersed in magnetized plasma, an ionized and electrically conducting gas. One of the mysteries in the astrophysical rotating systems has been the rate at which matter accretes from astrophysical disks onto a central body, such as a black hole. The angular momentum redistribution in these systems is observed to be far too rapid to be explained by known physical mechanisms. The resolution may be in the interaction between the rotating plasma and the magnetic field via the so-called Magneto-Rotational Instability (MRI). This instability leads to stretching and folding of magnetic field lines that connect the rotating plasma elements and contribute to the enhancement of turbulent angular momentum transport. This project will explore the MRI mechanism and associated magnetized plasma instabilities via three-dimensional computer simulations, with potential implications for improved understanding of both astrophysical and laboratory plasmas, including novel plasma confinement concepts for fusion energy development.This project will investigate key physical effects of global space and magnetic curvature in a rotating magnetized plasma which have not previously been taken into account. In particular, the subject of this study will be the onset and sustainment of three-dimensional non-axisymmetric perturbations in differentially rotating systems where exponentially growing axisymmetric MRI modes could be a partial driver. The question to be addressed is whether in a domain with spatial curvature global non-axisymmetric modes with real frequencies can persist. Distinct global modes, which are Alfven-continuum-driven modes due to global differential rotation and magnetic curvature, have recently been discovered. These are so-called magneto-curvature instability modes. Using both global simulations in a flow-driven media and analytical calculations, this project will investigate (1) the onset of the magneto-curvature global modes in magnetohydrodynamic (MHD) and Hall MHD regimes; and (2) the effect of these global modes on momentum transport, reconnection, and dynamo.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.

该奖项支持一项研究在许多天体物理系统和实验室实验中观察到的旋转磁化等离子体的物理学的研究。 关于黑洞和积聚磁盘的新观测发现越来越揭示我们的宇宙浸入了磁化等离子体中，这是一种电离和电动导电气体。天体物理旋转系统中的一个奥秘之一是从天体物理磁盘上产生的速度，例如黑洞。观察到这些系统中的角动量重新分布太快了，无法用已知的物理机制来解释。该分辨率可能是通过所谓的磁反转不稳定性（MRI）在旋转等离子体和磁场之间的相互作用。这种不稳定性导致磁场线的拉伸和折叠连接旋转等离子体元件，并有助于增强湍流角动量传输。 该项目将通过三维计算机模拟探索MRI机制和相关的磁化等离子体不稳定性，并有可能改善对天体物理和实验室等离子体的理解，包括新型的等离子体限制概念，用于融合能量。以前尚未考虑的旋转磁化等离子体中的全球空间和磁曲率。 特别是，这项研究的主题将是在差异旋转系统中的三维非轴对称扰动的发作和维持，在这些系统中，指数增长的轴对称MRI模式可能是部分驱动器。要解决的问题是，在具有空间曲率全局非轴对称模式的域中，具有真实频率的模式是否可以持续存在。 由于全局差异旋转和磁曲率，它们是Alfven-Continuum驱动的不同的全局模式，最近已被发现。 这些是所谓的磁性曲面不稳定性模式。在流动媒介和分析计算中，使用全球模拟，该项目将研究（1）磁性水力动力学（MHD）和HALL MHD机制中的磁性全球模式的发作； （2）这些全球模式对动量运输，重新连接和发电机的影响。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。