Consolidated Grant in Solar and Planetary Studies: Department of Applied Mathematics, University of Leeds

许多天体物理现象涉及磁场、旋转和湍流之间复杂的相互作用。我们打算进行一项系统和综合的研究方案，在太阳系和行星科学的各种情况下调查这种相互作用。我们将利用分析和数值技术的结合（包括应用为大规模并行机器优化的尖端数值算法）来理解这些现象。我们的统一理念是调查和解释这些天体物理流体中潜在的基本物理相互作用，同时也为最新的高分辨率观测提供理论基础。我们建议研究以下具体问题：(1)太阳物理学中最近最令人兴奋的观测发现是“太阳速斜”的发现，这是太阳深处一个夹在对流带和辐射带之间的高速剪切薄区。这在理论上是完全出乎意料的。我们将研究塔斜中以剪切为主的湍流的性质，以研究温度、磁场和角动量等量是如何传递的，从而理解为什么塔斜确实存在。(2)在太阳上，观测到的磁场存在于一定的时空尺度上，从大而持久的到小而短暂的。此外，太阳表面的对流也有一系列尺度，从超颗粒（直径约20,000公里）到颗粒（直径约1,000公里）。我们将研究对流和磁场之间的相互作用，以便在尺度上解释这些观测到的范围。(3)大规模的磁场通过太阳表面爆发，在太阳光球层中产生太阳黑子，并在太阳大气中引发有时剧烈的磁活动。高速斜中的速度剪切将弱的极向磁场缠绕成强的环向磁场，然后逃逸，上升并最终出现在地表。我们开发了一套新的方程，专门用来描述速斜的磁场。我们将用这些来解释逃逸磁场的规模和形态，然后将我们的发现与对新出现的太阳磁场的观测联系起来。大多数行星都有磁场，磁场的强度和空间形式差别很大。通过考虑特定行星的计算模型，我们将研究在气体巨星木星和土星以及冰巨星天王星和海王星中产生磁场的发电机机制的性质。我们的结果将与朱诺号木星任务的结果相关。

Many astrophysical phenomena involve the complex interaction between magnetic fields, rotation and turbulent fluid flows. We intend to undertake a systematic and integrated programme of research to investigate this interaction in a variety of contexts in solar system and planetary sciences. We shall utilise a combination of analytical and numerical techniques (including the application of cutting edge numerical algorithms optimised for use on massively parallel machines) to gain an understanding of such phenomena. Our unifying philosophy is to investigate and explain the underlying fundamental physical interactions in these astrophysical fluids whilst also providing a theoretical underpinning to the latest high-resolution observations. We propose to investigate the following specific problems:(1) The most exciting recent observational discovery in solar physics is the identification of the "solar tachocline", a thin region of strong velocity shear, deep in the Sun, sandwiched between the convective and radiative zones. This was entirely unexpected theoretically. We shall investigate the nature of the shear-dominated turbulent flow in the tachocline to investigate how quantities such as temperature, magnetic field and angular momentum are transported, and hence to understand why the tachocline does indeed exist.(2) On the Sun, magnetic field is observed to exist over a range of spatial and temporal scales, from the large and long-lived to the small and short-lived. Furthermore, the convection at the solar surface also has a range of scales, from supergranules (which are about 20,000 km across) down to granules (about 1000 km). We shall study the interaction between the convection and the magnetic fields to explain these observed ranges in scale.(3) The large-scale magnetic field erupts through the solar surface to cause sunspots in the photosphere and to trigger sometimes violent magnetic activity in the solar atmosphere. The velocity shear in the tachocline winds up the weak poloidal magnetic field into a strong toroidal field, which then escapes, to rise and eventually to appear at the surface. We have developed a new set of equations designed specifically to describe the magnetic field in the tachocline. We shall use these to explain the scale and morphology of the escaping magnetic field, and will then relate our findings to observations of emerging solar magnetic fields.(4) Most planets have magnetic fields, which vary widely in their strength and spatial form. By considering planet-specific computational models,we shall investigate the nature of the dynamo mechanism responsible for generating magnetic field in the gas giants, Jupiter and Saturn, and in the ice giants, Uranus and Neptune. Our results will be related to those of the JUNO mission to Jupiter.