The Astrophysics Research Programme at Newcastle University

拟议中的纽卡斯尔大学天体物理学研究方案包括六个独立的项目。虽然所有这些项目在本质上主要是理论性的，但大多数都是由最近的观察直接激发的。其中四个项目是相互关联的，因为它们都涉及导电流体（磁流体动力学）的运动，尽管涉及的尺度范围很广。在行星背景下，我们将通过考虑旋转球壳中的对流模型，研究内部流体运动通过发电机机制产生和维持大规模磁场的方式。我们还将研究大尺度极性反转的现象，其中大尺度行星磁场的径向分量改变符号。就太阳而言，最近对太阳表面的高分辨率观测揭示了小规模磁场的复杂分布。鉴于这些磁特征的起源仍在争论中，我们将研究这些磁场是由近地表对流运动产生的局部发电机产生的可能性。某些恒星系统的演化受到吸积盘的强烈影响，吸积盘是一种薄的结构，包含围绕星星轨道运动的物质。我们将使用一系列的分析（和半分析）技术来研究吸积盘和中心星星磁场之间的复杂耦合。在更大的尺度上，我们将考虑星际介质中的磁场。我们的目标是使用数值模拟来解决宇宙射线（带电粒子）如何通过真实的，发电机产生的星际磁场传播的基本问题，最终旨在生成可用于解释观测的结果。本提案中还有两个项目。在第一个这些，我们建议调查中子星的动力学，通过考虑一个模型的相互作用的漩涡在超流体（流体没有摩擦）。这是一个新兴的研究领域，可能与最近的实验室实验有关。在我们的宇宙学计划中，我们将考虑某些早期宇宙宇宙学模型的观测特征。这将与即将公开发布的普朗克卫星数据（预计在2013年1月）相配合，因此这是进行这项研究的绝佳时机。

The proposed astrophysics research programme at Newcastle University includes six independent projects. Although all of these projects are primarily theoretical in nature, most are directly motivated by recent observations. Four of the projects are linked, in the sense that they all deal with the motions of electrically-conducting fluids (magnetohydrodynamics), albeit over a vast range of scales. In the planetary context, we shall investigate the ways in which the internal fluid motions generate and sustain large-scale magnetic fields, via a dynamo mechanism, by considering a model of convection in a rotating spherical shell. We shall also investigate the phenomenon of large-scale polarity reversals, in which the radial component of the large-scale planetary magnetic field changes sign. In the case of the Sun, recent high resolution observations of the solar surface have revealed a complex distribution of small-scale magnetic fields. Given that the origin of these magnetic features is still under debate, we shall investigate the possibility that these fields are generated by a local dynamo resulting from the near-surface convective motions. The evolution of certain stellar systems is strongly influenced by the presence of an accretion disc, which is a thin structure containing material that is in orbital motion around the star. We shall use a range of analytic (and semi-analytic) techniques to investigate the complex coupling between an accretion disc and the central star's magnetic field. On much larger scales, we will consider magnetic fields in the interstellar medium. Our aim here is to use numerical simulations to address the fundamental question of how cosmic rays (charged particles) propagate through realistic, dynamo-generated, interstellar magnetic fields, ultimately aiming to generate results that can be used to interpret observations. There are two further projects in this proposal. In the first of these we propose to investigate the dynamics of neutron stars, by considering a model of interacting vortices in a superfluid (a fluid with no friction). This is an emerging area of research, with possible links to recent laboratory experiments. In our cosmology project, we shall consider the observational signatures of certain early universe cosmological models. This will tie in with the imminent public release of data from the Planck satellite (which is expected in January 2013), so this is an excellent time to be carrying out this research.