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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.

太阳的外层大气，即日冕，是一种被磁场渗透的动态等离子体。这个磁场负责创造长期存在的结构，如日冕环，将日冕加热到数百万度的温度，以及爆炸事件，如太阳耀斑和日冕物质抛射。这些强大的爆炸可以极大地影响地球及其周围的环境。它们产生了北极光和南极光，但也有可能破坏卫星、电网和管道，扰乱通信系统，并危及宇航员。要了解这些爆炸过程是如何发生的，需要对太阳磁场的行为有详细的了解，而太阳磁场的特征是其复杂的三维结构。获得这样的理解是本工作计划的目的，也是科学界理解天体物理等离子体结构形成这一更广泛目标的一部分。最近的观测进展使我们对太阳磁场有了越来越详细的了解。但空间分辨率的每一次提高都揭示了更精细的磁性结构，甚至达到了最先进望远镜的分辨率极限。更重要的是，时间节奏的每一次增加都揭示了在所有尺度上形成磁场和等离子体的更复杂的动力学。这个财团提案的首要主题是探索这种磁性复杂性的物理后果。我们的目标是了解这种复杂的磁场是如何形成的，它们是如何演变的，以及它们是如何积聚并爆炸性地释放大量能量的。这些问题具有挑战性，但如果我们要理解我们现在观察到的情况的全部含义，就必须解决这些问题。我们将解决这样的问题：是什么机制使太阳日冕如此热？太阳大气中的爆炸事件是如何发生的？我们是否可以开发新的工具来帮助分析这些复杂的磁场，我们是否可以将这些工具应用于全球范围内日冕的演变？是什么控制着日冕磁场可以放松到的最低能量状态，因此有多少能量可以用来加热等离子体？粒子是如何在特定的复杂磁场结构中加速的？我们将结合数值模拟和数学建模来解决这些问题，主要使用磁流体力学的非线性偏微分方程。该模型将采用最新一代太阳望远镜的输入，使用各种观测来验证和完善理论。综合起来，这些结果不仅有助于解释和预测日冕事件，还有助于回答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？”）还要了解整个宇宙中发生的一些基本等离子体物理过程。