Formation of super-Alfvenic electron jets during laser-driven magnetic reconnection at the Shenguang-II facility: particle-in-cell simulations
Formation of super-Alfvenic electron jets during laser-driven magnetic reconnection at the Shenguang-II facility: particle-in-cell simulations
复制标题
神光二号设施激光驱动磁重联过程中超阿尔芬电子射流的形成：细胞内粒子模拟
DOI：
10.1088/1367-2630/16/8/083021
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发表时间：
2014-08-08
影响因子：
3.3
通讯作者：
Zhang, Jie
中科院分区：
文献类型：
--
作者：
Lu, San;Lu, Quanming;Zhang, Jie
最近在神光二号(SG-II)设施中进行了高能量密度(HED)激光产生的等离子体的磁重联实验。用两束激光照射铝箔，产生两个等离子体气泡和一个“冻结”磁场。当两个具有相反磁场的气泡相互膨胀和挤压时，就会发生磁重联。在实验中，在激光驱动的磁重联的扇形流出区观察到了三个准直良好的高速电子喷流。基于二维胞内粒子(PIC)模拟，我们证明了激光驱动磁重联流出区的三个电子射流是超Alfvenic的，并揭示了它们的形成机制。边缘的两个超Alfvenic喷流是由外流电子形成的，外流电子在X线附近被重联电场加速后沿磁力线运动。中心的超阿尔文喷流是由来自等离子体气泡外部的电子形成的。这些电子被堆积区的磁场反射，同时被产生的电场加速。
Magnetic reconnection experiments in high-energy-density (HED) laser-produced plasmas have recently been conducted at the Shenguang-II (SG-II) facility. Two plasma bubbles and a 'frozen-in' magnetic field are generated by irradiating an Al foil using two laser beams. As the two bubbles with opposing magnetic fields expand and squeeze each other, magnetic reconnection occurs. In the experiments, three well-collimated high-speed electron jets are observed in the fanlike outflow region of the laser-driven magnetic reconnection. Based on two-dimensional (2D) particle-in-cell (PIC) simulations, we demonstrate that the three electron jets in the outflow region of laser-driven magnetic reconnection are super-Alfvenic, and their formation mechanism is also revealed in this paper. The two super-Alfvenic jets at the edge are formed by the outflow electrons, which move along magnetic field lines after they are accelerated in the vicinity of the X-line by the reconnection electric field. The super-Alfvenic jet at the center is formed by the electrons that come from the outside of the plasma bubbles. These electrons are reflected by the magnetic field in the pileup region and are meanwhile accelerated by the resulting electric field.