标题： 三维磁重联 显示英文标题

标题： Three-Dimensional Magnetic Reconnection

摘要： 磁场重联作为许多太阳、恒星、磁层和天体物理现象中的能量释放机制的重要性早已被认识到。 重联是磁场能够整体重构的唯一机制，从而使它们进入一个更低的能量状态。 在过去十年里，我们对三维重联的理解取得了一些重大进展。 特别是，三维磁流体力学（MHD）重联的关键特征已被确定。 例如，三维重联（i）可以在有或没有零点的情况下发生，（ii）在整个扩散区内连续且持续地发生，（iii）由反向旋转的流动驱动。 此外，对电阻性三维MHD磁场实验的分析揭示了一些与重联发生的位置和方式有关的有趣效应。 为了展示这些新特性，考虑了一系列恒定电阻率的实验，这些实验涉及在上覆场中两个极性相反的磁源之间的相互作用。 这种简单的相互作用代表了太阳磁场大气的一个典型构建模块。 通过追踪磁场拓扑的演化，我们可以解释重联发生的位置、方式以及速率。 值得注意的是，在任一时刻可以有高达五个能量释放位点（而潜在情况下只有一个），并且随着电阻率的减小（减少到原来的1/16），相互作用的持续时间增加（超过两倍）。 电阻率的降低还导致更高的峰值欧姆耗散和更多的总能量释放，这是由于更大的庞廷通量注入所致。 显示英文摘要

摘要： The importance of magnetic reconnection as an energy release mechanism in many solar, stellar, magnetospheric and astrophysical phenomena has long been recognised. Reconnection is the only mechanism by which magnetic fields can globally restructure, enabling them to access a lower energy state. Over the past decade, there have been some major advances in our understanding of three-dimensional reconnection. In particular, the key characteristics of 3D magnetohydrodynamic (MHD) reconnection have been determined. For instance, 3D reconnection (i) occurs with or without nulls, (ii) occurs continuously and continually throughout a diffusion region and (iii) is driven by counter rotating flows. Furthermore, analysis of resistive 3D MHD magnetic experiments have revealed some intriguing effects relating to where and how reconnection occurs. To illustrate these new features, a series of constant-resistivity experiments, involving the interaction of two opposite-polarity magnetic sources in an overlying field, are considered. Such a simple interaction represents a typical building block of the Sun's magnetic atmosphere. By following the evolution of the magnetic topology, we are able to explain where, how and at what rate the reconnection occurs. Remarkably there can be up to five energy release sites at anyone time (compared to one in the potential case) and the duration of the interaction increases (more than doubles) as the resistivity decreases (by a factor of 16). The decreased resistivity also leads to a higher peak ohmic dissipation and more energy being released in total, as a result of a greater injection of Poynting flux.