Magnetohydrodynamical Problems in the Galaxy

银河系中的磁流体动力学问题

• 批准号: 9423187
• 负责人: Steven Balbus
• 金额: $ 13.4万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-15 至 1999-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9423187&HistoricalAwards=false
• 关键词: Magnetohydrodynamical; Problems; Galaxy

94-23187 Balbus This proposal describes a number of different projects involving magnetohydrodynamical (MHD) studies of the Galaxy, having in common a concern with differential rotation and magnetic field. The effect of a weak magnetic field upon differentially rotating gas has been shown to be a local instability to axisymmetric disturbances, which can influence Galactic evolution. The projects are: (a) the extension and development of an existing Eulerian finite difference MHD code to include multiple fluids and finite resistivity; (b) a numerical investigation of the origin and evolution of the Galactic magnetic field, taking fully into account the presence of the weak field instability; (c) analytic and numerical studies of the Galactic halo, its local stability properties, and its relation to a two-dimensional magnetized wind; and (d) the development of an analytic formalism for, and explicit numerical solutions of the local gravitational collapse of an MHD fluid in the spiral arm regions of the Galaxy. This last project is motivated by the need to have a well-defined and quantitative procedure for establishing when bound structure drops out of the background interstellar gas flow.

94-23187 Balbus 该提案描述了涉及银河系磁流体动力学 (MHD) 研究的许多不同项目，它们的共同点都关注微分旋转和磁场。 弱磁场对差分旋转气体的影响已被证明是轴对称扰动的局部不稳定性，这会影响星系的演化。 这些项目是： (a) 现有欧拉有限差分 MHD 代码的扩展和开发，以包括多种流体和有限电阻率； (b) 对银河磁场的起源和演化进行数值研究，充分考虑到弱场不稳定性的存在； (c) 银河晕、其局部稳定性特性及其与二维磁化风的关系的分析和数值研究； (d) 开发银河系旋臂区域 MHD 流体局部引力塌缩的解析形式和显式数值解。 最后一个项目的动机是需要有一个明确的定量程序来确定束缚结构何时脱离背景星际气流。