In this review we focus on the fundamental theory of magnetohydrodynamic reconnection, together with applications to understanding a wide range of dynamic processes in the solar corona, such as flares, jets, coronal mass ejections, the solar wind and coronal heating. We summarise only briefly the related topics of collisionless reconnection, non-thermal particle acceleration, and reconnection in systems other than the corona. We introduce several preliminary topics that are necessary before the subtleties of reconnection can be fully described: these include null points (Sects. 2.1–2.2), other topological and geometrical features such as separatrices, separators and quasi-separatrix layers (Sects. 2.3, 2.6), the conservation of magnetic flux and field lines (Sect. 3), and magnetic helicity (Sect. 4.6). Formation of current sheets in two- and three-dimensional fields is reviewed in Sect. 5. These set the scene for a discussion of the definition and properties of reconnection in three dimensions that covers the conditions for reconnection, the failure of the concept of a flux velocity, the nature of diffusion, and the differences between two-dimensional and three-dimensional reconnection (Sect. 4). Classical 2D models are briefly presented, including magnetic annihilation (Sect. 6), slow and fast regimes of steady reconnection (Sect. 7), and non-steady reconnection such as the tearing mode (Sect. 8). Then three routes to fast reconnection in a collisional or collisionless medium are described (Sect. 9). The remainder of the review is dedicated to our current understanding of how magnetic reconnection operates in three dimensions and in complex magnetic fields such as that of the Sun’s corona. In Sects. 10–12, 14.1 the different regimes of reconnection that are possible in three dimensions are summarised, including at a null point, separator, quasi-separator or a braid. The role of 3D reconnection in solar flares (Sect. 13) is reviewed, as well as in coronal heating (Sect. 14), and the release of the solar wind (Sect. 15.2). Extensions including the role of reconnection in the magnetosphere (Sect. 15.3), the link between reconnection and turbulence (Sect. 16), and the role of reconnection in particle acceleration (Sect. 17) are briefly mentioned.

在这篇综述中，我们重点关注磁流体动力学重联的基本理论，以及理解日冕各种动态过程的应用，例如耀斑、喷流、日冕物质抛射、太阳风和日冕加热。我们仅简要总结了无碰撞重联、非热粒子加速以及日冕以外系统中重联的相关主题。我们介绍了在充分描述重连的微妙之处之前所必需的几个初步主题：这些主题包括零点（第 2.1-2.2 节）、其他拓扑和几何特征，例如分离线、​​分隔符和准分离线层（第 2.3 节、 2.6）、磁通量和磁力线守恒（第 3 节）以及磁螺旋度（第 4.6 节）。第 2 节回顾了二维和三维领域中当前片的形成。 5. 这些为讨论三维重联的定义和性质奠定了基础，其中包括重联的条件、通量速度概念的失败、扩散的本质以及二维和三维之间的差异维度重新连接（第 4 节）。简要介绍了经典的二维模型，包括磁湮没（第 6 节）、稳定重联的慢速和快速状态（第 7 节）以及非稳定重联，例如撕裂模式（第 8 节）。然后描述了在冲突或无冲突介质中快速重新连接的三种途径（第 9 节）。这篇评论的其余部分致力于我们目前对磁重联如何在三维和复杂磁场（例如太阳日冕）中运作的理解。昆虫。 10-12, 14.1 总结了在三个维度上可能的不同重连机制，包括零点、分隔符、准分隔符或编织层。回顾了 3D 重联在太阳耀斑（第 13 节）以及日冕加热（第 14 节）和太阳风释放（第 15.2 节）中的作用。简要提到了延伸，包括重联在磁层中的作用（第 15.3 节）、重联与湍流之间的联系（第 16 节）以及重联在粒子加速中的作用（第 17 节）。