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arXiv 2202.09073astro-ph.SRphysics.space-ph
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太阳爆发形成的磁通量绳的旋转

The Rotation of Magnetic Flux Rope Formed during Solar Eruption

Zhenjun Zhou, Chaowei Jiang, Rui Liu, Yuming Wang, Lijuan Liu, Jun Cui

摘要:

太阳暗条的爆发经常表现出围绕其上升方向的旋转运动,但仍然难以理解是什么机制支配着这种旋转,以及这种旋转如何与爆发前暗条(和同空间S形)的初始形态、暗条手征性和磁螺旋度相关。传统的观点认为旋转是磁通量绳(MFR)经历理想扭结不稳定性的结果,在解释这些关系时仍然存在混乱。在这里,我们提出了另一种解释的旋转在喷发过程中,通过分析磁流体动力学模拟,其中磁重联启动喷发从剪切拱廊配置和MFR形成在喷发过程中通过重联。模拟再现了一个反S形的MFR与右旋手征,和这个MFR的轴逆时针旋转,而上升,这与一个典型的灯丝喷发从双视角观察到的。通过计算模型化的MFR爆发过程中的扭曲和扭动数,发现伴随旋转,MFR轴的非局域扭动减小,而其周围磁力线的扭曲增加,这与将磁扭曲转化为MFR轴扭动的扭结不稳定性不同。

英文摘要:

The eruptions of solar filaments often show rotational motion about their rising direction, but it remains elusive what mechanism governs such rotation and how the rotation is related to the initial morphology of the pre-eruptive filament (and co-spatial sigmoid), filament chirality, and magnetic helicity. The conventional view regarding the rotation as a result of a magnetic flux rope (MFR) under-going the ideal kink instability still has confusion in explaining these relationships. Here we proposed an alternative explanation for the rotation during eruptions, by analyzing a magnetohydrodynamic simulation in which magnetic reconnection initiates an eruption from a sheared arcade configuration and an MFR is formed during eruption through the reconnection. The simulation reproduces a reverse S-shaped MFR with dextral chirality, and the axis of this MFR rotates counterclockwise while rising, which compares favorably with a typical filament eruption observed from dual viewing angles. By calculating the twist and writhe numbers of the modeled MFR during its eruption, we found that accompanied with the rotation, the nonlocal writhe of the MFR's axis decreases while the twist of its surrounding field lines increases, and this is distinct from the kink instability, which converts magnetic twist into writhe of the MFR axis.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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