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

太阳和行星研究综合资助：利兹大学应用数学系

• 批准号: ST/S00047X/1
• 负责人: Christopher Jones
• 金额: $ 51.28万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FS00047X%2F1
• 关键词: Consolidated; Grant; Solar; Planetary; Studies

Many astrophysical phenomena involve the complex interaction between magnetic fields, rotation and turbulent fluid flows. We will 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. We propose to investigate the following specific problems:(1) 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). A new anelastic code has been developed in Leeds, and we will use this to explore the interaction between the convection and the magnetic fields to explain these observed ranges in scale. We will address the important issue of whether the observed small-scale magnetic field is broken-down large-scale field, or whether it is generated afresh by a small-scale dynamo. We shall also explore the role of the near-surface shear layer to see how it affects the solar magnetic field just below the photosphere. (2) A key observational discovery in solar physics was the identification of the "solar tachocline", a thin region of strong velocity shear, deep in the Sun, sandwiched between the convective and radiative zones. Recent satellite observations of the Sun have revealed new short period activity cycles in addition to the 11 year activity cycle. Long term observations of bright points in the corona have revealed slow waves. These waves and activity cycles most likely arise in the tachocline. We will explore what types of waves the tachocline can support, and how they develop in the nonlinear regime. This will enable us to discover if these new observations can be understood in terms of tachocline dynamics, and how these signals in the deep interior are transmitted to the solar surface.(3) The nature and strength of the magnetic field in the radiative interior below the tachocline is a major unknown of solar research. We will explore a mechanism known as magnetic buoyancy, by which magnetic fields rise upwards. This is known to be important nearer the surface, but it might also play a role in the deepest regions of the Sun. There is an analogy between magnetic buoyancy and double diffusive convection, which occurs in our oceans. It has recently been discovered that by forming density layers, the transport of heat and salt in the ocean can be much enhanced. By studying three-dimensional, nonlinear models to investigate this layering process in the magnetic context, we will explore whether such layering can occur in the deep solar interior. This will provide important new constraints on the magnetic field in the solar radiative zone. (4) The Juno space mission has sent back stunning pictures of Jupiter's surface, and we now also have much more accurate data about Jupiter's magnetic field and its gravity field. The gravity field data has shown that the strong winds seen at the surface of Jupiter penetrate deep into the interior of the planet. We also have similar data for Saturn from the Cassini Grand Finale, when the Cassini probe dived into Saturn, recording close up data just before it was swallowed up. We now plan to assimilate this accurate data into our dynamo models for giant planets, and hence constrain interior models in a way that has hitherto not been possible. We aim to discover if Jupiter has a dense, compact core or a large, dilute core as recently suggested. We will also explore whether the deep winds predicted by our dynamo models are consistent with the observed winds.

许多天体物理现象涉及磁场、自转和湍流之间的复杂相互作用。我们将开展一项系统和综合的研究方案，在太阳系和行星科学的各种背景下调查这种相互作用。我们将利用分析和数值技术（包括应用最先进的数值算法优化用于大规模并行机）的组合，以获得对这种现象的理解。本文拟研究以下几个具体问题：（1）在太阳上，观测到磁场存在于从大的、长寿命的到小的、短寿命的一系列时空尺度上。此外，太阳表面的对流也有一系列的尺度，从超颗粒（直径约20，000公里）到颗粒（约1000公里）。利兹开发了一个新的滞弹性代码，我们将使用它来探索对流和磁场之间的相互作用，以解释这些观测范围的规模。我们将讨论一个重要的问题，即观测到的小尺度磁场是被分解的大尺度磁场，还是由小尺度发电机重新产生的。我们还将探讨近地表剪切层的作用，看看它如何影响光球层下方的太阳磁场。(2)太阳物理学的一个关键观测发现是发现了“太阳速跃层”，这是太阳深处夹在对流区和辐射区之间的一个薄的强烈速度切变区。最近对太阳的卫星观测显示，除了11年的活动周期外，还有新的短期活动周期。对日冕中亮点的长期观测揭示了慢波。这些波和活动周期最有可能出现在速跃层中。我们将探讨速跃层可以支持什么类型的波，以及它们如何在非线性状态下发展。这将使我们能够发现这些新的观测结果是否可以从速跃层动力学的角度来理解，以及这些信号是如何在内部深处传输到太阳表面的。(3)在速跃层下面的辐射内部磁场的性质和强度是太阳研究的一个主要未知数。我们将探索一种被称为磁浮力的机制，通过这种机制，磁场向上上升。这在靠近太阳表面的地方很重要，但它也可能在太阳最深处发挥作用。磁浮力与我们海洋中发生的双重扩散对流有相似之处。最近发现，通过形成密度层，海洋中的热量和盐的传输可以大大增强。通过研究三维非线性模型来研究磁场背景下的分层过程，我们将探索这种分层是否会发生在太阳内部深处。这将为太阳辐射区的磁场提供重要的新约束。(4)朱诺号太空使命已经发回了木星表面令人惊叹的照片，我们现在也有了关于木星磁场和重力场的更准确的数据。重力场数据显示，木星表面的强风深入到行星内部。我们也有类似的数据，土星从卡西尼大结局，当卡西尼探测器潜入土星，记录近距离数据之前，它被吞噬。我们现在计划将这些精确的数据同化到我们的巨行星发电机模型中，从而以一种迄今为止不可能的方式约束内部模型。我们的目标是发现木星是否有一个密集的，紧凑的核心或一个大的，稀释的核心，因为最近建议。我们还将探讨我们的发电机模型预测的深风是否与观测到的风一致。

项目成果

The deep winds of Jupiter

木星的深风

• DOI: 10.1038/s41550-023-02129-z
• 发表时间: 2023
• 期刊: Nature Astronomy
• 影响因子: 14.1
• 作者: Jones C

Convective turbulent viscosity acting on equilibrium tidal flows: new frequency scaling of the effective viscosity

作用于平衡潮汐流的对流湍流粘度：有效粘度的新频率缩放

• DOI: 10.1093/mnras/staa2216
• 发表时间: 2020
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Duguid C

Fully developed anelastic convection with no-slip boundaries

具有无滑移边界的完全发展的滞弹性对流

• DOI: 10.1017/jfm.2021.905
• 发表时间: 2021
• 期刊: Journal of Fluid Mechanics
• 影响因子: 3.7
• 作者: Jones C

Anelastic torsional oscillations in Jupiter's metallic hydrogen region

木星金属氢区域的滞弹性扭转振荡

• DOI: 10.1016/j.epsl.2019.04.042
• 发表时间: 2019
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: Hori K

Angular momentum transport, layering, and zonal jet formation by the GSF instability: nonlinear simulations at a general latitude

GSF 不稳定性引起的角动量传输、分层和纬向射流形成：一般纬度的非线性模拟

• DOI: 10.48550/arxiv.2005.04941
• 发表时间: 2020
• 作者: Barker A