Impact of magnetic complexity in solar and astrophysical plasmas: Dundee-Durham consortium

这个项目是邓迪大学和达勒姆大学研究人员在天体物理等离子体中复杂磁场行为的成功合作的延续。磁场在天体物理学中无处不在。在离地球最近的地方，它们是在旋转的恒星和行星（如太阳和地球）内部产生的，但它们渗透了大部分中间空间——例如，地球位于磁化的太阳风中。在更远的地方，可以观察到大到整个星系的磁场，小到中子星的磁场。在我们用现代望远镜仔细观察它们的地方，比如在太阳的大气层中，我们发现这些磁场非常复杂，具有最小可观测尺度的空间结构和显著的动力学行为。磁场在决定许多这类系统的行为方面起着至关重要的作用——然而，它们无处不在的复杂性的含义在很大程度上仍未被探索和理解。磁场最壮观的影响常常出现在恒星可见表面上方的脆弱等离子体中。例如，在太阳的大气层中，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。这些强大的爆炸会导致地球上的主要空间天气事件，产生北极光和南极光，但也有可能对工程系统造成破坏性的经济影响，从卫星和通信系统到电网和管道。然而，与从遥远的磁星观测到的巨大爆发相比，这些太阳磁爆炸弱得可怜；也许这并不奇怪，因为它们拥有宇宙中已知最强的磁场。该联盟的首要目标是探索磁复杂性的原因，并确定其可能的大规模后果。我们能解释最新一代的高分辨率观测结果吗？即使我们不能直接观察到，这种小规模的复杂性是否也能产生重大影响？磁场的动态行为是如何导致太阳爆发或磁星爆发的？财团内的各种项目将为一系列不同的装置进行理论和数值建模，仔细选择以模拟天体物理等离子体的基本特征，包括日冕环、太阳耀斑、中子星、日冕物质抛射和太阳风的来源。重要的是，建模将采用最新一代望远镜的输入-我们的几个太阳模型将直接“数据驱动”，并且观测将用于验证输出。我们的许多模型预测将根据即将到来的新观测进行调整，包括来自DKIST和帕克太阳探测器的观测。除了探索天体物理等离子体的基本物理学外，从我们的模拟中获得的见解将在空间天气预报领域得到实际应用。越来越明显的是，预测空间天气事件的发生和影响不能依赖于静态的外推模型，而需要对太阳磁场的动态行为和潜在的精细结构有深刻的理解。

This project is a continuation of a successful collaboration between the researchers of the Universities of Dundee and Durham on the behaviour of complex magnetic fields in astrophysical plasmas. Magnetic fields are ubiquitous in astrophysics. Closest to home they are generated inside rotating stars and planets (like the Sun and Earth), but they permeate much of the intervening space - for example, the Earth sits within the magnetised solar wind. Further afield, magnetic fields are observed on scales as vast as that of whole galaxies and as small as that of neutron stars. Where we observe them closely with modern telescopes, such as in the Sun's atmosphere, we find that these magnetic fields are highly complex, having spatial structure down to the smallest observable scales and significant dynamical behaviour. Magnetic fields play a crucial role in determining the behaviour of many of these systems - however, the implications of their ubiquitous complexity remain largely unexplored and poorly understood.The most spectacular impacts of magnetic fields are often found in the tenuous plasma above the visible surface of stars. In the Sun's atmosphere, for example, the 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. Yet these solar magnetic explosions are pitifully weak by comparison with the huge bursts observed from distant magnetars; perhaps not surprising given that these have the strongest magnetic fields known in the Universe. The overarching aim of the consortium is to explore the causes of magnetic complexity, and to determine its possible large-scale consequences. Can we explain the latest generation of high-resolution observations? Can this small-scale complexity have a significant effect even when we cannot observe it directly? How does the dynamical behaviour of magnetic fields lead to solar eruptions or magnetar bursts?The various projects within the consortium will carry out theoretical and numerical modelling for a range of different setups, carefully chosen to model the essential features of astrophysical plasmas including coronal loops, solar flares, neutron stars, and the sources of coronal mass ejections and the solar wind. Importantly, the modelling will take input from the latest generation of telescopes - several of our solar models will be directly "data-driven", and observations will be used to validate output. Many of our model predictions will be tailored to upcoming new observations, including those from DKIST and Parker Solar Probe. As well as probing the fundamental physics of astrophysical plasmas, the insight gained from our simulations will have practical application in the space-weather forecasting community. 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, and potentially the fine structure, of the Sun's magnetic field.