Constraining the Magneto-Rotational Instability in Accretion Disks with Simulations of Dwarf Novae and X-ray Binary Outbursts

通过模拟矮新星和 X 射线双星爆发来约束吸积盘中的磁旋转不稳定性

• 批准号: 1412417
• 负责人: Omer Blaes
• 金额: $ 23.54万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-15 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1412417&HistoricalAwards=false
• 关键词: Constraining; Magneto; Rotational; Instability; Accretion; Constraining; Magneto; Rotational; Instability; Accretion

Material falling onto dwarf stars, neutron stars, and black holes, a process called accretion, powers some of the most energetic and fascinating astronomical sources. Because rotation is common in the Universe, most accretion systems form disks swirling around the central gravitating object, where material must transfer away its rotational inertia, or angular momentum, before continuing inwards. The matter flowing inwards also spends time in the disk converting energy into the outgoing radiation by which these objects can be observed. This research will apply new methods to understanding the process of angular momentum transport in disks around white dwarf stars, and may finally settle whether the currently dominant model is in fact correct.Magneto-rotational instability (MRI) turbulence has become the dominant research framework for understanding angular momentum transport and the release of accretion power in accretion disks across all of astrophysics, from proto-planetary disks to active galactic nuclei. Although the ultimate goal is to model observed sources, little attention has been paid so far to dwarf nova outbursts in accretion disks orbiting white dwarfs, which offer the most interesting observational constraints on angular momentum transport. Using vertically-stratified, radiation magneto-hydrodynamic (MHD) shearing box simulations of MRI turbulence, this research will build on recent results showing intermittent thermal convection. Three new studies are planned: (1) ensure that the thermal convection is numerically resolved, and understand how it enhances turbulent transport, (2) incorporate non-ideal MHD in the largely neutral state to see if MRI turbulent transport can be sustained in the quiescent state; and (3) incorporate lessons learned about the vertical structure and angular momentum transport into existing alpha-based models of the hydrogen ionization disk instability. This direct confrontation between the MRI model and observations will firm up the theoretical foundation of the hydrogen ionization disk instability, and allow observations of dwarf novae and low mass X-ray binaries to constrain more effectively the properties of MRI turbulence.One graduate student will develop their thesis from this project, several undergraduates are expected to be involved, and the research will inform public talks, including a new one being developed specifically on the science contained in this work.

落在矮星，中子星和黑洞上的材料，这是一种称为积聚的过程，为一些最有活力，最迷人的天文来源提供动力。 由于旋转在宇宙中很常见，因此大多数吸积系统形成圆盘在中央引力物体周围旋转，在此材料必须在继续向内之前将其旋转惯性或角动量转移。 向内流动的物质还花费时间在磁盘上转换为可以观察到这些物体的传出辐射。 This research will apply new methods to understanding the process of angular momentum transport in disks around white dwarf stars, and may finally settle whether the currently dominant model is in fact correct.Magneto-rotational instability (MRI) turbulence has become the dominant research framework for understanding angular momentum transport and the release of accretion power in accretion disks across all of astrophysics, from proto-planetary disks to active galactic nuclei. 尽管最终的目标是建模观察到的来源，但到目前为止，几乎没有引起人们的注意，即在绕着白色矮人的积聚磁盘中爆发，这为角动量运输提供了最有趣的观察性约束。 使用垂直分层的辐射磁磁动力学（MHD）剪切盒模拟MRI湍流，这项研究将基于最新结果，显示出间歇性热对流。 计划了三项新的研究：（1）确保热对流可以在数值上解决，并了解其如何增强湍流运输，（2）在很大程度上中性状态中纳入了非理想的MHD，以查看是否可以在静态状态下进行MRI湍流运输； （3）将有关垂直结构和角动量传输的经验教训纳入现有的基于Alpha的基于氢离子磁盘不稳定性的模型。 MRI模型和观察之间的这种直接对抗将巩固氢离子化磁盘不稳定性的理论基础，并允许观察到矮人Novae和低质量X射线二进制二进制文件，以更有效地限制MRI湍流的特性。一个研究生的研究将在该项目中开发出来，并将其专门介绍为新的研究，并将其介绍为新的研究，并将涉及的一项研究涉及，并且涉及一定程度的研究。包含在这项工作中。