Quadrupolar and hexapolar Hall magnetic field during asymmetric magnetic reconnection without a guide field

作者：Longlong Sang, Quanming Lu, Rongsheng Wang, Kai Huang, Shui Wang · 发表于：Physics of Plasmas · 年份：2018 · DOI：10.1063/1.5030439 · 被引用次数：10 · 研究领域：Ionosphere and magnetosphere dynamics、Plasma Diagnostics and Applications、Magnetic confinement fusion research

In this paper, by taking advantage of a two-dimensional particle-in-cell simulation model, we study the structure of the out-of-plane magnetic field (Hall magnetic field) during asymmetric magnetic reconnection without a guide field, and the associated in-plane current system is also analyzed. The evolution of asymmetric reconnection has two stages. At the first stage, the electrons move toward the X line along the separatrix in the magnetosheath side, and depart from the X line along the separatrix in the magnetosphere side. Another electron flow toward the X line exists above the separatrix in the magnetosphere side. The resulted in-plane current system, which is mainly determined by electron dynamics, generates the quadrupolar structure of the Hall magnetic field, where the two quadrants in the magnetosheath side are much stronger than those in the magnetosphere side. At the second stage, besides these electron flows, an additional electron flow away from the X line is formed along the magnetic field below the separatrix in the magnetosheath side. A hexapolar structure of the Hall magnetic field is then generated by such a current system.