近日，北京师范大学仲佳勇团队的最新研究发现了由强激光产生的湍流磁重联。相关论文于2023年1月16日发表在《自然—物理学》杂志上。
研究团队演示了激光产生的等离子体在照射固体靶时产生的湍流磁重联。湍流是由强烈驱动的磁重联产生的，它将电流片碎片化，研究团队还观察到多个磁岛和磁通管的形成。他们的发现再现了太阳耀斑观测的关键特征。
在动力学模拟的支持下，研究团队揭示了湍流磁重联中电子加速的机制，该机制由平行电场主导，而betatron机制起冷却作用，费米加速可以忽略不计。由于他们实验室实验的条件可扩展到天体物理等离子体的条件，因此他们的结果适用于太阳耀斑的研究。
据介绍，在天体物理等离子体中，湍流磁重联可能是太阳耀斑的触发因素，并经常出现在较长的拉伸和碎裂的电流片中。帕克太阳探测器、太阳动力学观测站和原位卫星任务最近的观测结果与预期的湍流重联信号一致。然而，潜在的机制，包括储存在太阳磁场中的磁能是如何消散的，仍然不清楚。
附：英文原文
Title: Turbulent magnetic reconnection generated by intense lasers
Author: Ping, Yongli, Zhong, Jiayong, Wang, Xiaogang, Han, Bo, Sun, Wei, Zhang, Yapeng, Yuan, Dawei, Xing, Chunqing, Wang, Jianzhao, Liu, Zhengdong, Zhang, Zhe, Qiao, Bin, Zhang, Hua, Li, Yutong, Zhu, Jianqiang, Zhao, Gang, Zhang, Jie
Issue&Volume: 2023-01-16
Abstract: Turbulent magnetic reconnection is believed to occur in astrophysical plasmas, and it has been suggested to be a trigger of solar flares. It often occurs in long stretched and fragmented current sheets. Recent observations by the Parker Solar Probe, the Solar Dynamics Observatory and in situ satellite missions agree with signatures expected from turbulent reconnection. However, the underlying mechanisms, including how magnetic energy stored in the Sun’s magnetic field is dissipated, remain unclear. Here we demonstrate turbulent magnetic reconnection in laser-generated plasmas created when irradiating solid targets. Turbulence is generated by strongly driven magnetic reconnection, which fragments the current sheet, and we also observe the formation of multiple magnetic islands and flux-tubes. Our findings reproduce key features of solar flare observations. Supported by kinetic simulations, we reveal the mechanism underlying the electron acceleration in turbulent magnetic reconnection, which is dominated by the parallel electric field, whereas the betatron mechanism plays a cooling role and Fermi acceleration is negligible. As the conditions in our laboratory experiments are scalable to those of astrophysical plasmas, our results are applicable to the study of solar flares.
DOI: 10.1038/s41567-022-01855-x
Source: https://www.nature.com/articles/s41567-022-01855-x