Plasma heating of small-scale loops in the solar atmosphere

环是塑造太阳大气的磁骨架的基本结构。在宁静的太阳下，等离子体在一百万度的温度下发出的极端紫外线辐射大多局限于小规模的磁环。因此，了解加热这些回路中等离子体的物理机制至关重要。该项目的主要目标是进一步加深我们对小规模回路中等离子体加热机制的理解。这些小尺度环状星团被称为日冕亮点(CBPS)。我们将研究在太阳大气和太阳风的质量和能量转移中，大气层中的喷发所起的作用。尽管过去几年在这一研究领域取得了进展，但仍然存在许多基本的悬而未决的问题，需要进一步进行全面的观察和理论建模。一些悬而未决的问题是：哪种小规模环路系统的等离子体加热模型与观测到的小规模环路的形态、等离子体演化和磁场性质最匹配？在被限制在小尺度日冕磁环结构中的等离子体加热中，磁重联和磁声波传播的可能的相互作用是什么？个别小规模环路的强度变化是否与微耀斑或纳米耀斑的加热有关，还是其他物理机制在起作用？在这个项目的第一阶段，我们将推导出小尺度磁环的等离子体加热模型的观测约束。通过将模型预测的加热率与环长和磁通量的比例与观测结果进行比较，将得到模型约束。模型约束也将从磁环的形态和演化及其等离子体性质中获得。这将在新兴的CBP中完成，它由光谱和成像数据中记录的许多环路形成，但也根据环路的演化和寿命来形成。在第二阶段，我们将对微耀斑和环状增亮及其与各种加热过程的联系进行统计调查。在第三阶段，我们将通过统计和案例研究来研究CBP的演化和喷发，以及它们与羽流和磁场折返的可能联系。为了实现新项目的目标，我们将使用最先进的空间观测(IRIS、Hinode、太阳轨道器和帕克太阳探测器)和地面观测站(快速成像太阳光谱仪、瑞典太阳望远镜和丹尼尔·K·井上太阳望远镜)。还将使用最先进的模型，包括线性磁流体静力和非线性无力场外推、磁摩擦和3D辐射MHD，或与观测结果进行比较。该项目将提供关于小规模回路等离子加热的基准知识。

Loops are the fundamental structures that shape the magnetic skeleton of the solar atmosphere. The extreme-ultra-violet emission from plasma at a temperature of a million degrees in the quiet Sun is mostly confined to small-scale magnetic loops. Therefore, it is imperatively important to understand the physical mechanisms that heat the plasma in these loops. The main objective of the project is to further advance our understanding of the mechanisms of plasma heating in small-scale loops. Clusters of these small-scale loops are as coronal bright points (CBPs) known. We will investigate what is the role of eruptions in CBPs in the mass and energy transfer in the solar atmosphere and the solar wind. Although the past several years steps forward in this research domain were made, numerous fundamental open questions remain that require further comprehensive observational and theoretical modelling. Some of the open questions are: Which plasma-heating models of small-scale loop systems match best the observed morphology, evolution of plasma and magnetic field properties of small-scale loops? What is the possible interplay of magnetic reconnection and magneto-acoustic wave propagation in the heating of plasma confined in small-scale coronal magnetic loop structures? Are intensity variations in individual small-scale loops related to micro- or nanoflare heating, or are other physical mechanisms at play? In phase one of this project, we will derive the observational constraints of plasma-heating models of small-scale magnetic loops. The model constraints will be obtained through the comparison of model-predicted scaling of heating rates with loop lengths and magnetic fluxes with those determined observationally. Model constraints will also be obtained from the morphology and evolution of magnetic loops and their plasma properties. This will be done in emerging CBPs, which are formed from many loops as recorded in spectroscopic and imaging data, but also from the evolution and lifetime of the loops. In phase 2, we will conduct a statistical investigation of microflares and loop brightenings and their link to various heating processes. In phase 3, we will investigate CBP evolution and eruptions and their possible link to plumes and magnetic switchbacks both statistically and through case studies. To achieve the goals of the new project we will use state-of-the-art observations from space (IRIS, Hinode, Solar Orbiter, and Parker Solar Probe) and ground-based observatories (Fast Imaging Solar Spectrograph, Solar Swedish Telescope, and Daniel K. Inouye Solar Telescope). A state-of-the-art modelling including linear magneto-hydrostatic and non-linear force-free field extrapolations, magneto-frictional, and 3D radiative MHD will also be employed or compared with observations. The project will provide benchmarking knowledge on plasma heating of small-scale loops.