Complex magnetic fields: An enigma of solar plasmas (Dundee-Durham Consortium)

复杂磁场：太阳等离子体之谜（邓迪-达勒姆联盟）

基本信息

批准号：
ST/K000993/1
负责人：
Gunnar Hornig
金额：
$ 78万
依托单位：
University of Dundee
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FK000993%2F1
关键词：
Complex magnetic fields enigma solar

项目摘要

The outer atmosphere of the Sun, the solar corona, 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 can greatly influence the Earth and its surrounding environment. They create the Northern and Southern lights, but also have the potential to damage satellites, power grids and pipelines, disrupt communications systems, and endanger astronauts. Understanding how these explosive processes take place requires a detailed understanding of the behaviour of the Sun's magnetic field, which is characterised by its complex three-dimensional structure. Gaining such an understanding is the aim of this work programme and is part of a wider goal in the scientific community of understanding the formation of structures in astrophysical plasmas.Recent observational advances are providing us with a more and more detailed view of the Sun's magnetic field. But each increase in spatial resolution reveals finer scale magnetic structures, down to the resolution limit of even the most advanced telescopes. What is more, each increase in time cadence reveals more complex dynamics that shape the magnetic field and plasma on all scales. The over-arching theme of this consortium proposal is to explore the physical consequences of this magnetic complexity. We aim to understand how such complex magnetic fields are formed, how they evolve, and how they can build up and explosively release extreme amounts of energy. These questions are challenging, but must be addressed if we are to understand the full implications of what we are now observing.We will address problems such as: What is the mechanism that makes the solar corona so hot? How do explosive events occur in the Sun's atmosphere? Can we develop new tools to help analyse these complex magnetic fields, and can we apply these tools to the evolution of the corona on global scales? What controls the lowest energy state to which the magnetic field of the corona can relax, and therefore how much energy is available to heat the plasma? How are particles accelerated in particular complex magnetic field structures?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. The modelling will take input from the latest generation of solar telescopes, using various observations to verify and refine the theory. Combined, the results should help not only to explain and predict events in the solar corona and help 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?") but also to understand some of the basic plasma physical processes that go on throughout the Universe.

太阳的外部气氛，太阳电晕，是一个动态的等离子体，磁场渗透。该磁场负责创建长寿结构，例如冠状环，将电晕加热至数百万度的温度以及爆炸性事件，例如太阳耀斑和冠状质量弹出。这些强大的爆炸会极大地影响地球及其周围环境。它们创造了北极光和南部的灯光，但也有可能损害卫星，电网和管道，破坏通信系统以及危害宇航员。了解这些爆炸性过程是如何进行的，需要对太阳磁场的行为有详细的理解，这是其复杂的三维结构的特征。获得这样的理解是该工作计划的目的，并且是理解天体物理等离子体结构形成的科学界的一个更广泛目标的一部分。当时的观察进步为我们提供了对太阳磁场的越来越详细的看法。但是，空间分辨率的每种增加都会揭示出更细的磁性结构，直到甚至最先进的望远镜的分辨率极限。更重要的是，时间节奏的每种增加都会揭示出更复杂的动力学，从而在所有尺度上塑造磁场和等离子体。该财团提案的总体主题是探索这种磁复杂性的物理后果。我们旨在了解如何形成这种复杂的磁场，如何发展以及它们如何建立和爆炸性地释放极端的能量。这些问题具有挑战性，但是如果我们要了解现在观察到的内容的全部含义，必须解决这些问题。我们将解决以下问题：什么使太阳能电晕如此热的机制是什么？爆炸性事件如何发生在太阳的大气中？我们可以开发新工具来帮助分析这些复杂的磁场，并且我们可以将这些工具应用于全球尺度上的电晕的演变吗？是什么控制电晕的磁场可以放松的最低能量状态，因此可以使用多少能量来加热等离子体？在特别的复杂磁场结构中，颗粒如何加速？我们将使用数值模拟和数学建模的组合来解决这些问题，主要是使用磁性流体动力学的非线性偏微分方程。该建模将利用各种观察结果来验证和完善理论，从最新一代的太阳能望远镜中获取输入。结合结合起来，结果不仅应该有助于解释和预测太阳能电晕中的事件，并有助于回答STFC的科学路线图挑战b：2（“太阳如何影响地球环境以及太阳系的其余部分？”），还了解一些在整个宇宙中持续的基本基本等离子体物理过程。