标题： 快速磁重联：经典、霍尔和相对论等离子体中的“理想”撕裂不稳定性 显示英文标题

标题： Fast magnetic reconnection: The "ideal" tearing instability in classic, Hall, and relativistic plasmas

摘要： 磁重联被认为是天体物理学中许多爆发现象的驱动因素，从太阳到磁星和蟹状星云中的伽马射线耀斑。 然而，经典磁流体动力学（MHD）模型中的重联速率远不足以解释这些观测结果。 最近发现，当电流片变得足够薄时，撕裂不稳定性重联速率会变得“理想”，即在宏观阿尔芬时间尺度上失稳，而不管等离子体的 Lundquist 数是多少。 在这里，我们展示了经典、霍尔和相对论 regimes 中的二维可压缩 MHD 模拟。 特别是，首次在霍尔-MHD 中研究了次级撕裂不稳定性的发展。 在相对论 MHD 的框架下，我们总结了 Del Zanna 等人的主要结果 [1]：相对论撕裂不稳定性被发现极其快速，重联速率约为光穿越时间的倒数，这符合解释高能爆发现象的要求。 显示英文摘要

摘要： Magnetic reconnection is believed to be the driver of many explosive phenomena in Astrophysics, from solar to gamma-ray flares in magnetars and in the Crab nebula. However, reconnection rates from classic MHD models are far too slow to explain such observations. Recently, it was realized that when a current sheet gets sufficiently thin, the reconnection rate of the tearing instability becomes "ideal", in the sense that the current sheet destabilizes on the "macroscopic" Alfv\'enic timescales, regardless of the Lundquist number of the plasma. Here we present 2D compressible MHD simulations in the classical, Hall, and relativistic regimes. In particular, the onset of secondary tearing instabilities is investigated within Hall-MHD for the first time. In the frame of relativistic MHD, we summarize the main results from Del Zanna et al. [1]: the relativistic tearing instability is found to be extremely fast, with reconnection rates of the order of the inverse of the light crossing time, as required to explain the high-energy explosive phenomena.