Collisionless magnetic reconnection in a plasmoid chain
Collisionless magnetic reconnection in a plasmoid chain
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DOI：
10.5194/npg-19-145-2012
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发表时间：
2012-02
影响因子：
2.2
通讯作者：
S. Markidis;P. Henri;G. Lapenta;A. Divin;M. Goldman;David E. Newman;S. Eriksson
中科院分区：
文献类型：
--
作者：
S. Markidis;P. Henri;G. Lapenta;A. Divin;M. Goldman;David E. Newman;S. Eriksson
抽象的。用二维粒子模拟方法研究了等离子体体链的形成和演化的动力学特征。由于撕裂不稳定性，在多个X点处发生了磁重联。等离子体会通过不断的聚合形成并增大尺寸。每个链状等离子体都显示出一个强大的面外核心磁场和一个驱动聚结过程的面外电子电流。聚结过程中X点的消失是由于反重联，即等离子体流入和流出相对于原始重联流型相反的磁重联。反重联的特征是霍尔磁场四极特征。这里揭示了两个新的动力学特征，这两个特征是以前的等离子体体链进化研究没有报道的。首先，强电场在平面内垂直于分离物发展，并驱动等离子体中的离子动力学。其次，几个双极电场结构被定域在等离子体体链附近。对电子分布函数和相空间的分析表明，存在对两流不稳定的逆流电子束，以及沿重联分离线的相空间电子空穴。
Abstract. The kinetic features of plasmoid chain formation and evolution are investigated by two dimensional Particle-in-Cell simulations. Magnetic reconnection is initiated in multiple X points by the tearing instability. Plasmoids form and grow in size by continuously coalescing. Each chain plasmoid exhibits a strong out-of plane core magnetic field and an out-of-plane electron current that drives the coalescing process. The disappearance of the X points in the coalescence process are due to anti-reconnection, a magnetic reconnection where the plasma inflow and outflow are reversed with respect to the original reconnection flow pattern. Anti-reconnection is characterized by the Hall magnetic field quadrupole signature. Two new kinetic features, not reported by previous studies of plasmoid chain evolution, are here revealed. First, intense electric fields develop in-plane normally to the separatrices and drive the ion dynamics in the plasmoids. Second, several bipolar electric field structures are localized in proximity of the plasmoid chain. The analysis of the electron distribution function and phase space reveals the presence of counter-streaming electron beams, unstable to the two stream instability, and phase space electron holes along the reconnection separatrices.