Electron dynamics in collisionless magnetic reconnection |
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Authors: | QuanMing Lu RongSheng Wang JinLin Xie Can Huang San Lu Shui Wang |
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Institution: | [1]CAS Key Laboratory of Basic Plasma Physics, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China; [2]Institute of Geology of Geophysics, Chinese Academy of Sciences, Beijing 100029, China; [3]CAS Key Laboratory of Basic Plasma Physics, School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China |
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Abstract: | Magnetic reconnection provides a physical mechanism for fast energy conversion from magnetic energy to plasma kinetic energy.
It is closely associated with many explosive phenomena in space plasma, usually collisionless in character. For this reason,
researchers have become more interested in collisionless magnetic reconnection. In this paper, the various roles of electron
dynamics in collisionless magnetic reconnection are reviewed. First, at the ion inertial length scale, ions and electrons
are decoupled. The resulting Hall effect determines the reconnection electric field. Moreover, electron motions determine
the current system inside the reconnection plane and the electron density cavity along the separatrices. The current system
in this plane produces an out-of-plane magnetic field. Second, at the electron inertial length scale, the anisotropy of electron
pressure determines the magnitude of the reconnection electric field in this region. The production of energetic electrons,
which is an important characteristic during magnetic reconnection, is accelerated by the reconnection electric field. In addition,
the different topologies, temporal evolution and spatial distribution of the magnetic field affect the accelerating process
of electrons and determine the final energy of the accelerated electrons. Third, we discuss results from simulations and spacecraft
observations on the secondary magnetic islands produced due to secondary instabilities around the X point, and the associated
energetic electrons. Furthermore, progress in laboratory plasma studies is also discussed in regard to electron dynamics during
magnetic reconnection. Finally, some unresolved problems are presented. |
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Keywords: | magnetic reconnection reconnection electric field secondary island electron acceleration |
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