Kink instability evidenced by analyzing the leg rotation of a filament

Abstract

Kink instability is a possible mechanism for solar filament eruption. However, the twist of a solar filament is very difficult to directly measure from observation. In this paper, we carried out the measurement of the twist of a solar filament by analyzing its leg rotation. An inverse S-shaped filament in active region NOAA 11485 was observed by the Atmospheric Imaging Assembly (AIA) of Solar Dynamics Observatory (SDO) on 2012 May 22. During its eruption, the leg of the filament exhibited a significant rotation motion. The 304 Å images were used to uncurl along the circles, whose centers are the axis of the filament's leg. The result shows that the leg of the filament rotated up to about 510 degrees (about 2.83$\pi$) around the axis of the filament within twenty-three minutes. The maximal rotation speed reached 100 degrees per minute (about 379.9 km/s at radius 18${}^{\prime }$${}^{\prime }$), which is the fastest rotation speed that has been reported. We also calculated the decay index along the polarity inversion line in this active region and found that the decline of the overlying field with height is not so fast enough to trigger the torus instability. According to the condition of kink instability, it is indicating that the kink instability is the trigger mechanism for the solar filament eruption.

16 pages, 7 figures, Accepted for publication in ApJ

References in corpus (3)

• Ideal kink instability of a magnetic loop equilibrium
• Formation of current sheets and sigmoidal structure by the kink instability of a magnetic loop
• Observations and modeling of the early acceleration phase of erupting filaments involved in coronal mass ejections

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• Partial eruption of a filament with twisting nonuniform fields
• Unambiguous Evidence of Filament Splitting-Induced Partial Eruptions
• The eruption of a small-scale emerging flux rope as the driver of an M-class flare and a coronal mass ejection
• Interaction of Two Active Region Filaments Observed by NVST and SDO
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• Dynamics evolution of a solar active-region filament from quasi-static state to eruption: rolling motion, untwisting motion, material transfer, and chirality
• High-resolution Observations of a Flux Rope with the Interface Region Imaging Spectrograph
• Rapid Rotation of an Erupting Prominence and the Associated Coronal Mass Ejection on 13 May 2013
• Untwisting and Disintegration of a Solar Filament Associated with Photospheric Flux Cancellation
• The Formation and Eruption of A Sigmoidal Filament Driven by Rotating Network Magnetic Fields
• Trigger of successive filament eruptions observed by SDO and STEREO