近日，韩国浦项科技大学Young Dae Yoon团队研究了动力学湍流通过三维重连驱动MHD平衡变化。2025年8月6日出版的《自然》杂志发表了这项成果。

从磁流体动力学（MHD）到非MHD尺度的跨尺度耦合对于解释自然界中爆炸事件的观测非常重要，例如太阳耀斑和地磁风暴。实验和观察也把其与高能粒子和x射线的出现联系起来。然而，这种多尺度物理如何影响重联的突然发生仍然未知。

研究组报告了实验室实验的观察结果，涉及两个带有电子束的通量绳，它们诱导磁湍流，然后突然合并成一个单一的结构，改变了MHD制度中的磁拓扑结构。两个独立的电子束沿着磁力线发射，形成单独的通量绳，其漂移速度高于周围的Alfvén速度，通过波束驱动的不稳定性有效地驱动磁湍流，从湍流功率谱的增加水平推断。

实验观察，包括高能粒子的出现、离子温度的升高和通量绳特性的变化，表明光束驱动的湍流驱动了三维（3D）重连。进行了三维细胞内粒子模拟，成功地再现了实验的关键方面。这些结果直接解释了非MHD动力学过程如何在多个尺度上进行，从而导致全球MHD变化。

附：英文原文

Title: Kinetic turbulence drives MHD equilibrium change via 3D reconnection

Author: Park, Jong Yoon, Yoon, Young Dae, Hwang, Yong-Seok

Issue&Volume: 2025-08-06

Abstract: Cross-scale coupling from magnetohydrodynamics (MHD) to non-MHD scales is important in interpreting observations of explosive events in nature, such as solar flares and geomagnetic storms1,2. Experiments and observations also link it to the emergence of energetic particles and X-rays3. However, how this multi-scale physics affects the abrupt onset of reconnection remains unknown. Here we report observations from laboratory experiments involving two flux ropes with electron beams that induce magnetic turbulence and then abruptly merge into a single structure, altering the magnetic topology in the MHD regime. Two separate electron beams are launched along magnetic field lines and form individual flux ropes with a drift velocity higher than the ambient Alfvén velocity, effectively driving magnetic turbulence through beam-driven instabilities, as inferred from the increased level of the turbulent power spectrum. Experimental observations, including the appearance of energetic particles, increased ion temperature and changes in the characteristics of the flux ropes, suggest that beam-driven turbulence drives three-dimensional (3D) reconnection. 3D particle-in-cell simulations are performed, which successfully reproduce the key aspects of the experiment. These results directly explain how non-MHD kinetic processes progress through multiple scales to induce global MHD changes.

DOI: 10.1038/s41586-025-09345-9

Source: https://www.nature.com/articles/s41586-025-09345-9