Magnetic islands in collisionless magnetic reconnection

LU Quanming; WANG Rongsheng; HUANG Kai; WANG Shui

doi:10.3969/j.issn.0253-2778.2020.09.002

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Open Access JUSTC Review Article

Magnetic islands in collisionless magnetic reconnection

1.
CAS Key Lab 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

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https://doi.org/10.3969/j.issn.0253-2778.2020.09.002

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Corresponding author: LU Quanming(corresponding author), male, born in 1969, PhD/Changjiang Distinguished Prof. He received his BS degree from Nanjing University in 1990, and his MS and PhD degrees from University of Science and Technology of China in 1993 and 1996, respectively. He had been a postdoctor from 1996-1998 at Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, and from 1998-2000 at Tsukuba University, Japan. He joined the faculty of University of Science and Technology of China as associate professor in the Department of Earth and Space Sciences in 2000. He was promoted to full professor in 2003. His research field has been focused on space plasma physics, and he has published more than 200 SCI papers in international high-level academic journals including Nature Physics, Nature Communications and Physical Review Letters. E-mail: qmlu@ustc.edu.cn
Received Date: 16 August 2020
Rev Recd Date: 15 September 2020
Publish Date: 30 September 2020

Abstract Full text PDF

Abstract

Abstract

The roles of magnetic islands were reviewed in two essential aspects of collisionless magnetic reconnection： are rapid dissipation from magnetic energy to plasma kinetic energy and generation of energetic electrons. The current sheet around the X line may be extended and unstable to the tearing mode instability. Secondary magnetic islands are generated and then consequentially interact each other in the extended current sheet. Such a nonstationary magnetic reconnection can maintain a large reconnection rate for a long time and efficiently dissipate magnetic energy. Electrons can be accelerated inside magnetic islands by Fermi and betatron mechanisms, as well as by reconnection electric field in the vicinity of the X line. The interaction of magnetic islands can result in further electron acceleration. These acceleration processes can make energetic electrons possess a power-law spectrum.

Abstract

The roles of magnetic islands were reviewed in two essential aspects of collisionless magnetic reconnection： are rapid dissipation from magnetic energy to plasma kinetic energy and generation of energetic electrons. The current sheet around the X line may be extended and unstable to the tearing mode instability. Secondary magnetic islands are generated and then consequentially interact each other in the extended current sheet. Such a nonstationary magnetic reconnection can maintain a large reconnection rate for a long time and efficiently dissipate magnetic energy. Electrons can be accelerated inside magnetic islands by Fermi and betatron mechanisms, as well as by reconnection electric field in the vicinity of the X line. The interaction of magnetic islands can result in further electron acceleration. These acceleration processes can make energetic electrons possess a power-law spectrum.