中国物理B ›› 2022, Vol. 31 ›› Issue (8): 89401-089401.doi: 10.1088/1674-1056/ac76ab

所属专题： TOPICAL REVIEW — Celebrating 30 Years of Chinese Physics B

• • 上一篇    

Collisionless magnetic reconnection in the magnetosphere

Quanming Lu(陆全明)1,2,†, Huishan Fu(符慧山)3,4, Rongsheng Wang(王荣生)1,2, and San Lu(卢三)1,2   

  1. 1 CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;
    2 CAS Center for Excellence in Comparative Planetology, Hefei 230026, China;
    3 School of Space and Environment, Beihang University, Beijing 100191, China;
    4 Key Laboratory of Space Environment Monitoring and Information Processing, Ministry of Industry and Information Technology, Beijing 100191, China
  • 收稿日期:2022-04-18 修回日期:2022-06-03 接受日期:2022-06-08 出版日期:2022-07-18 发布日期:2022-07-29
  • 通讯作者: Quanming Lu E-mail:qmlu@ustc.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 42174181), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB 41000000), and the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (Grant No. QYZDJ-SSW-DQC010).

Collisionless magnetic reconnection in the magnetosphere

Quanming Lu(陆全明)1,2,†, Huishan Fu(符慧山)3,4, Rongsheng Wang(王荣生)1,2, and San Lu(卢三)1,2   

  1. 1 CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;
    2 CAS Center for Excellence in Comparative Planetology, Hefei 230026, China;
    3 School of Space and Environment, Beihang University, Beijing 100191, China;
    4 Key Laboratory of Space Environment Monitoring and Information Processing, Ministry of Industry and Information Technology, Beijing 100191, China
  • Received:2022-04-18 Revised:2022-06-03 Accepted:2022-06-08 Online:2022-07-18 Published:2022-07-29
  • Contact: Quanming Lu E-mail:qmlu@ustc.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 42174181), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB 41000000), and the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (Grant No. QYZDJ-SSW-DQC010).

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摘要： Magnetic reconnection underlies the physical mechanism of explosive phenomena in the solar atmosphere and planetary magnetospheres, where plasma is usually collisionless. In the standard model of collisionless magnetic reconnection, the diffusion region consists of two substructures: an electron diffusion region is embedded in an ion diffusion region, in which their scales are based on the electron and ion inertial lengths. In the ion diffusion region, ions are unfrozen in the magnetic fields while electrons are magnetized. The resulted Hall effect from the different motions between ions and electrons leads to the production of the in-plane currents, and then generates the quadrupolar structure of out-of-plane magnetic field. In the electron diffusion region, even electrons become unfrozen in the magnetic fields, and the reconnection electric field is contributed by the off-diagonal electron pressure terms in the generalized Ohm's law. The reconnection rate is insensitive to the specific mechanism to break the frozen-in condition, and is on the order of 0.1. In recent years, the launching of Cluster, THEMIS, MMS, and other spacecraft has provided us opportunities to study collisionless magnetic reconnection in the Earth's magnetosphere, and to verify and extend more insights on the standard model of collisionless magnetic reconnection. In this paper, we will review what we have learned beyond the standard model with the help of observations from these spacecraft as well as kinetic simulations.

关键词: collisionless magnetic reconnection, magnetosphere

Abstract: Magnetic reconnection underlies the physical mechanism of explosive phenomena in the solar atmosphere and planetary magnetospheres, where plasma is usually collisionless. In the standard model of collisionless magnetic reconnection, the diffusion region consists of two substructures: an electron diffusion region is embedded in an ion diffusion region, in which their scales are based on the electron and ion inertial lengths. In the ion diffusion region, ions are unfrozen in the magnetic fields while electrons are magnetized. The resulted Hall effect from the different motions between ions and electrons leads to the production of the in-plane currents, and then generates the quadrupolar structure of out-of-plane magnetic field. In the electron diffusion region, even electrons become unfrozen in the magnetic fields, and the reconnection electric field is contributed by the off-diagonal electron pressure terms in the generalized Ohm's law. The reconnection rate is insensitive to the specific mechanism to break the frozen-in condition, and is on the order of 0.1. In recent years, the launching of Cluster, THEMIS, MMS, and other spacecraft has provided us opportunities to study collisionless magnetic reconnection in the Earth's magnetosphere, and to verify and extend more insights on the standard model of collisionless magnetic reconnection. In this paper, we will review what we have learned beyond the standard model with the help of observations from these spacecraft as well as kinetic simulations.

Key words: collisionless magnetic reconnection, magnetosphere

中图分类号:  (Space plasma physics)

  • 94.05.-a
94.30.cp (Magnetic reconnection) 94.30.-d (Physics of the magnetosphere)