Dynamics of Complex Magnetic Fields: From the corona to the solar wind

该项目名为“复杂磁场的动力学：从日冕到太阳风”，是邓迪大学和达勒姆大学研究人员就太阳大气中磁场的纠缠性质进行的成功合作的延续。日冕是太阳的外层大气，是一种被磁场渗透的动态等离子体。这个磁场负责创造长寿命的结构，如日冕环，将日冕加热到数百万度的温度，并导致爆炸事件，如太阳耀斑和日冕物质抛射。这些强烈的爆炸导致了地球上的重大空间天气事件，造成了南北光，但也可能对从卫星和通信系统到电网和管道的工程系统造成破坏性的经济影响。越来越明显的是，预测空间气象事件的发生和影响不能依赖静态外推模型，而需要对太阳磁场的动态行为有深入的了解。太阳日冕中复杂的三维磁场的细节是空间天气事件链中的关键部分。与此同时，重要的是要了解这些磁性结构在太阳风中向地球进行时的演变方式。该联盟旨在解决这些问题，作为科学界了解天体物理等离子体中结构形成的更广泛目标的一部分。该联盟内的不同项目将专注于事件链的不同方面。我们将解决这样的问题：我们如何才能最好地模拟日冕磁结构随时间的积累？在日冕中形成的扭曲的磁通量绳的性质是什么，当它们喷发并形成日冕物质抛射时，它们的结构是如何演变的？太阳风的非稳定慢成分的来源在哪里？是什么机制让太阳的日冕如此炎热？是什么控制了日冕磁场可以松弛到的最低能量状态，因此有多少能量可以用来加热等离子体？我们能预测相应弛豫态的平衡结构吗？这些问题中的每一个都是理解太阳日冕磁场中动态、多尺度过程的挑战。我们将使用数值模拟和数学建模相结合的方法来解决这些问题，主要使用磁流体动力学的非线性偏微分方程。重要的是，建模将采用最新一代的太阳望远镜--我们的几个模型将直接由“数据驱动”，观测结果将被用来验证输出(从日冕磁场的全球模拟到对缓慢太阳风和地球磁云结构的预测)。综合起来，这些结果将有助于预测和解释日冕中的事件，回答STFC的科学路线图挑战B：2(“太阳如何影响地球和太阳系其他部分的环境？”)，以及理解宇宙中发生的一些基本的等离子体物理过程。

This project, entitled "Dynamics of Complex Magnetic Fields: From the corona to the solar wind'', is a continuation of a successful collaboration between the researchers of the Universities of Dundee and Durham on the entangled nature of magnetic fields in the solar atmosphere. The corona, the outer atmosphere of the Sun, is a dynamic plasma permeated by a magnetic field. This magnetic field is responsible for creating long-lived structures such as coronal loops, for heating the corona to its multi-million degree temperatures, and for explosive events such as solar flares and coronal mass ejections. These powerful explosions lead to major space weather events at Earth, creating the Northern and Southern lights but also having the potential for damaging economic impacts on engineered systems, ranging from satellites and communication systems to power grids and pipelines. It is becoming apparent that forecasting the occurrence and impact of space weather events cannot rely on static extrapolation models but requires a deep understanding of the dynamical behaviour of the Sun's magnetic field. Details of the complex, three-dimensional magnetic fields in the Sun's corona are a critical part of the space weather chain of events. At the same time, it is important to understand the manner in which these magnetic structures evolve in the solar wind as they are carried out towards Earth. This consortium aims to address these questions, as part of a wider goal in the scientific community of understanding the formation of structures in astrophysical plasmas.Different projects within the consortium will focus on different aspects of the chain of events. We will address problems such as: How can we best model the build-up of coronal magnetic structure over time? What is the nature of the twisted magnetic "flux ropes" that form in the corona, and how does their structure evolve as they erupt and form coronal mass ejections? Where is the source of the non-steady slow component of the solar wind? What is the mechanism that makes the Sun's corona so hot? What controls the lowest energy state to which the coronal magnetic field can relax, and therefore how much energy is available to heat the plasma? Can we predict the equilibrium structure of the corresponding relaxed states? Common to each of these questions is the challenge of understanding dynamical, multi-scale processes in the Sun's coronal magnetic field.We will use a combination of numerical simulations and mathematical modelling to tackle these questions, primarily using the non-linear partial differential equations of magnetohydrodynamics. Importantly, the modelling will take input from the latest generation of solar telescopes - several of our models will be directly "data-driven", and observations will be used to validate output (from global simulations of the coronal magnetic field to predictions of the slow solar wind and structure of magnetic clouds at Earth). Combined, the results will help to predict and explain events in the solar corona and to answer STFC's Science Roadmap Challenge B:2 ("How does the Sun influence the environment of the Earth and the rest of the Solar System?"), as well as to understand some of the basic plasma physical processes that go on throughout the Universe.