Magnetic buoyancy instabilities in stellar interiors

恒星内部的磁浮力不稳定性

• 批准号: 2760611
• 金额: --
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2760611
• 关键词: Magnetic; buoyancy; instabilities; stellar; interiors

Magnetic buoyancy instabilities can occur for horizontal magnetic fields varying with depth, which ultimately arise because such a field can support a heavy gas by virtue of the pressure it exerts. These instabilities have been studied in both the linear and nonlinear regimes for a number of years. However, many unsolved problems remain regarding both the linear and nonlinear properties of the instability. Recently, a set of asymptotically-reduced models, that are more amenable to computation and analysis than the fully compressible system, have been derived that describe magnetic buoyancy instabilities in certain parameter regimes. The linear properties of magnetic buoyancy instabilities have not been explored (at all or fully) in several of these models previously. In this project we will first explore the linear properties of magnetic buoyancy instabilities in several of these reduced models, before turning to simulate their nonlinear evolution. It is known that in certain parameter regimes magnetic buoyancy instabilities are double-diffusive, and the nonlinear evolution can lead to layering in the field and density profiles. These issues, and the resulting turbulent transport properties, will be explored with numerical simulations with the goal of understanding their role in stellar and planetary interiors.

随着深度变化的水平磁场可能会出现磁浮力不稳定，最终会出现这种情况，因为这样的磁场可以通过施加的压力来支持重气。这些不稳定性已经在线性和非线性区域进行了多年的研究。然而，关于不稳定性的线性和非线性性质，仍有许多未解决的问题。最近，一组比完全可压缩系统更易于计算和分析的渐近约化模型被导出，它们描述了在某些参数范围内的磁浮力不稳定性。在以前的几个模型中，磁浮力不稳定性的线性特性还没有(完全或完全)被探索过。在这个项目中，我们将首先在几个这样的简化模型中探索磁浮力不稳定性的线性特性，然后转向模拟它们的非线性演化。众所周知，在某些参数范围内，磁浮力不稳定性是双扩散的，非线性演化会导致磁场和密度分布的分层。这些问题以及由此产生的湍流传输特性将通过数值模拟进行探索，目的是了解它们在恒星和行星内部的作用。