Hydrodynamic and magnetohydrodynamic instabilities in differentially-rotating stars

日震学和星震学的观测进展突出表明，我们对太阳和其他恒星稳定分层辐射区中的化学混合和角动量输运机制的理解不足。该项目将研究恒星和行星内部可能有助于混合和角动量传输的各种流体动力学或磁流体动力学不稳定性。这些过程可以改变恒星的内部自转、结构和演化年龄，但在当前的恒星模型中，它们通常被忽略或以特设的方式建模。该项目将涉及线性分析和数值模拟相结合，以了解一个或多个这些不稳定性的属性，并确定其非线性行为。该项目的最终目标之一是了解这些不稳定性的非线性结果，另一个是提供简单的参数化的混合和角动量输运性质，可以纳入恒星模型。

Observational advances in helio- and astero-seismology have highlighted our poor understanding of the mechanisms of chemical mixing and angular momentum transport in the stably-stratified radiation zones of the Sun and other stars. This project will study various hydrodynamic or magnetohydrodynamic instabilities in stellar and planetary interiors that could contribute to mixing and angular momentum transport. These processes can modify the internal rotations, structures and evolutionary ages of stars, but they are commonly either neglected or modelled in an ad-hoc manner in current stellar models. This project will involve a combination of linear analysis and numerical simulations to understand the properties of one or more of these instabilities, and to determine their nonlinear behaviour. One of the ultimate goals of this project is to understand the nonlinear outcome of these instabilities and another is to provide simple parameterisations of their mixing and angular momentum transport properties that can be incorporated in stellar models.