The so-called regularized Biot-Savart laws (RBSLs) provide an efficient and flexible method for modeling pre-eruptive magnetic configurations of coronal mass ejections (CMEs) whose characteristics are constrained by observational images and magnetic-field data. This method allows one to calculate the field of magnetic flux ropes (MFRs) with small circular cross-sections and an arbitrary axis shape. The field of the whole configuration is constructed as a superposition of (1) such a flux-rope field and (2) an ambient potential field derived, for example, from an observed magnetogram. The RBSL kernels are determined from the requirement that the MFR field for a straight cylinder must be exactly force-free. For a curved MFR, however, the magnetic forces are generally unbalanced over the whole path of the MFR. To minimize these forces, we apply a modified Gauss-Newton method to find optimal MFR parameters. This is done by iteratively adjusting the MFR axis path and axial current. We then try to relax the resulting optimized configuration in a subsequent line-tied zero-beta magnetohydrodynamic simulation toward a force-free equilibrium. By considering two models of the sigmoidal pre-eruption configuration for the 2009 February 13 CME, we demonstrate how this approach works and what it is capable of. We show, in particular, that the building blocks of the core magnetic structure described by these models match to morphological features typically observed in such type of configurations. Our method will be useful for both the modeling of particular eruptive events and theoretical studies of idealized pre-eruptive MFR configurations.
Analysis of the Helical Kink Stability of Differently Twisted Magnetic Flux Ropes
磁通量绳（MFR）通常被认为是控制螺旋度从太阳到日光层的传输的磁性结构。它们在螺旋状组织的磁结构中夹带一个受限的等离子体，并能够引起地磁活动。最惠国制度的形成、演变和扭曲分布是引起激烈辩论的问题。虽然到目前为止已经提出了不同的扭曲轮廓，但还没有一个被彻底探索。这项工作的目的是提出一个理论研究的条件下，具有不同的扭曲配置文件是扭结稳定的，从而揭示了上述方面的一些光。磁场根据Nieves-Chinchilla等人（Astrophys. J. 823，27，2016）以及Lundquist和Gold-Hoyle模型，并且用基于Linton、Longcope和Fisher（Astrophys. J. 469，954，1996）。结果进行了讨论，在MFR旋转，磁力，反向手征的情况下，和整个日光层的膨胀，除其他外，提供了一个理论背景，以提高目前的理解的内部磁场配置的日冕物质抛射（CME）。帕克太阳探测器或太阳轨道飞行器等新任务获得的数据将有机会通过观察比以往任何时候都更接近太阳的MFR来探索这些结果和想法。
Extremely Large Extreme-ultraviolet Late Phase Powered by Intense Early Heating in a Non-eruptive Solar Flare
我们分析并模拟了2011年9月9日发生的M1.2级非爆发性太阳耀斑。耀斑具有强的极紫外暖日冕发射（$\sim$ 3~MK）的晚相峰，峰值发射是主耀斑峰值的1.3倍以上。观测到多个耀斑带，其演化过程表现为两个阶段的能量释放过程。一个非线性无力场（NLFFF）外推揭示了存在一个磁零点，一个扇脊结构，和两个磁通绳嵌入在扇圆顶。耀斑中的磁重联是由其中一条磁通绳的不稳定和上升驱动的。在第一阶段，快速上升的磁通绳驱动在零点和周围的准分界线层（QSL）的重联，而在第二阶段，重联主要发生在最终停止的磁通绳拉伸的两个腿之间的场线。晚期相环主要由第一级QSL重联产生，而第二级重联则负责加热主耀斑环。第一阶段的重联被认为是更强大的，导致一个非常强大的EUV后期。我们发现，延迟出现的晚相峰主要是由于长的晚相环的冷却过程长。使用基于热演化的环路模型（EBTEL），我们模拟了后期环路的EUV辐射。模拟结果表明，后期回路的峰值加热速率为1.1 erg cm $^{-3}$ s $^{-1}$，明显高于以往的数值。
Probing the magnetic field of a coronal mass ejection with PSR J1022+1001
Auckland University of Technology（奥克兰理工大学）；GeoSphere Austria（奥地利地球科学中心）；University of Graz（格拉茨大学）；Universitá degli Studi di Milano-Bicocca（米兰比可卡大学）；INAF - Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；INFN, Sezione di Milano-Bicocca（意大利国家核物理研究所米兰比可卡分部）；University Orleans（奥尔良大学）；Observatoire de Paris（巴黎天文台）；CNRS（法国国家科学研究中心）；CNES（法国国家空间研究中心）；Observatoire Radioastronomique de Nançay (ORN)（南希射电天文台）；Université d’Orléans（奥尔良大学）；University of Zagreb（萨格勒布大学）
A Data-constrained Magnetohydrodynamic Simulation of Successive X-class Flares in Solar Active Region 13842. II. Dynamics of the Solar Eruption Associated with the X9.0 Solar Flare
Statistical insights on the decorrelation lengths of solar wind parameters at L1 point under varying conditions
Department of Physics and Astronomy, Iowa City（爱荷华大学物理与天文学系）；Dept. of Physics, Assam（阿萨姆大学物理系）；Centre for Atmospheric Studies, Assam（阿萨姆大气研究中心）；Physical Research Laboratory, Ahmedabad（艾哈迈达巴德物理研究所）；Indian Institute of Technology (IIT), Gandhinagar（甘地纳加尔印度理工学院）
