Recently, Dr. XU Shanshan, associate Prof. MEI Zhixing and Prof. LIN Jun from the "Solar Activity and CME Theory Research Group" of Yunnan Observatories, Chinese Academy of Sciences (CAS), and Prof. ZHONG Jiayong from Beijing Normal University have published the latest research on laser-driven magnetic reconnection. The research investigated the fine structure of laser-driven magnetic reconnection in the laboratory using numerical simulations. This research were recently published in Physics of Plasma.

The extreme astrophysical environment and the physical processes that occur therein can be reproduced in the laboratory using energetic lasers and plasma. Thus, many energetic phenomena in this environment have been investigated in laboratories by exploring the consequences of irradiating laser beams directed at metal targets. Several studies on astrophysical phenomena have been conducted in laboratories with the help of laser-driven magnetic reconnection.

This work describes a numerical study of the magnetic reconnection between two magnetic fields of opposite polarity. The magnetic fields are created by an electric current in a coil connected to two metal disks. One of the disks is irradiated by a strong laser beam, whereby large amounts of free electrons flow toward the other disk, constituting a closed circuit for the electric current flowing through the coil. Two parallel coils are arranged to connect the two disks, and irradiation of the laser beam on one disk results in parallel electric currents in the two coils, inducing two magnetic fields of opposite polarity in the region between them. The magnetic reconnection that occurs in this region is three-dimensional.

The researchers investigate this three-dimensional magnetic reconnection via magnetohydrodynamic(MHD) numerical simulations using the MPI-AMRVAC software. The characteristics of the Petschek-type magnetic reconnection are observed for the first time in such numerical simulations of magnetic reconnection. Changes in the shape of the magnetic field lines form the boundary of the dissipation region and the outflow region. Moreover, the thermal plasma generated by reconnection is strongly confined to the region where the reconnecting current sheet and the slow-mode shock are located, and no leaks of thermal plasma are observed. “Comparisons with existing laboratory experiment results confirm that our numerical simulations reproduce the experimental outcomes and provide reasonable explanations for the results observed in laboratories,” said Dr. XU.

This work was supported by the Project of Chinese Academy of Sciences, the National Natural Science Foundation of China, the Applied Basic Research of Yunnan Province, the Yunnan Province Scientist Workshop of Solar Physics, as well as the Yunnan Province Yunling Scholar Project. The calculations in this work were performed on the cluster in the Computational Solar Physics Laboratory of the Yunnan Observatories.

Contact:
MEI Zhixing
Yunnan Observatories, CAS
Email: meizhixing@ynao.ac.cn