There is growing evidence that when magnetic reconnection occurs in high Lundquist number plasmas such as in the Solar Corona or the Earth's Magnetosphere it does so within a fragmented, rather than a smooth current layer. Within the extent of these fragmented current regions the associated magnetic flux transfer and energy release occurs simultaneously in many different places. This investigation focusses on how best to quantify the rate at which reconnection occurs in such layers. An analytical theory is developed which describes the manner in which new connections form within fragmented current layers in the absence of magnetic nulls. It is shown that the collective rate at which new connections form can be characterized by two measures; a total rate which measures the true rate at which new connections are formed and a net rate which measures the net change of connection associated with the largest value of the integral of $E_{\|}$ through all of the non-ideal regions. Two simple analytical models are presented which demonstrate how each should be applied and what they quantify.
Velocity space origins of pressure-strain interaction in multi-population distributions and its application to magnetic reconnection
Clemson University（克莱姆森大学）；West Virginia University（西弗吉尼亚大学）；Bates College（贝茨学院）；Northumbria University（诺森比亚大学）；U. S. Naval Research Laboratory（美国海军研究实验室）；Princeton University（普林斯顿大学）；Princeton Plasma Physics Laboratory（普林斯顿等离子体物理实验室）；University of New Hampshire（新罕布什尔大学）；University of Iowa（爱荷华大学）
Quantifying Properties of Photospheric Magnetic Cancellations in the Quiet Sun Internetwork
我们分析了瑞典1米太阳望远镜的分光偏振数据，以研究安静的太阳光球中小尺度磁抵消的物理特性。具体来说，我们看了完整的斯托克斯偏振配置文件沿Fe I 557.6 nm和Fe I 630.1 nm线测量的CRISP成像光谱偏振仪（CRISP）研究时间演变的视线（LOS）磁场在42.5分钟的安静的太阳演变。从这个磁图序列中，我们直观地识别出38个抵消事件。然后，我们使用另一种特征跟踪算法（YAFTA）来表征这些磁抵消的物理特性。我们发现，在每个事件中，磁通量的平均$1.6\times10^{16}$ Mx被抵消，平均抵消率为$3.8\times10^{14}$ Mx s $^{-1}$。推导出的抵消通量与强下行流有关，平均速度为$V_\mathrm{LOS}\approx1.1$ km s $^{-1}$。我们的研究结果表明，每个事件的平均寿命是$9.2$分钟，平均$44.8\%$的初始磁通被取消。我们对磁通量的估计提供了一个下限，因为所研究的磁抵消事件具有非常接近仪器噪声水平的磁场值。我们没有观察到水平磁场的取消网站，因此不能得出结论，事件是否相关的结构，可能会导致磁重联。
Calculation of Field Line Slippage Rates in Coronal Simulations
University of Glasgow（格拉斯哥大学）；University of Trento（特伦托大学）；Montana State University（蒙大拿州立大学）；University of Newcastle（纽卡斯尔大学）；Durham University（杜伦大学）；University of Dundee（邓迪大学）；University of Michigan（密歇根大学）
