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Title: PARTIAL ERUPTION OF A FILAMENT WITH TWISTING NON-UNIFORM FIELDS

Abstract

The eruption of a filament in a kinklike fashion is often regarded as a signature of kink instability. However, the kink instability threshold for the filament’s magnetic structure is not widely understood. Using Hα observations from the New Vacuum Solar Telescope, we present a partial eruptive filament. During the eruption, the filament thread appeared to split from its middle and to break out in a kinklike fashion. In this period, the remaining filament material stayed below and erupted without the kinking motion later on. The coronal magnetic field lines associated with the filament are obtained from nonlinear force-free field extrapolations using the twelve-minute-cadence vector magnetograms of the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory. We studied the extrapolated field lines passing through the magnetic dips which are in good agreement with the observed filament. The field lines are non-uniformly twisted and appear to be composed of two twisted flux ropes winding around each other. One of them has a higher twist than the other, and the flux rope with the higher twist has its dips aligned with the kinking eruptive thread at the beginning of its eruption. Before the eruption, moreover, the flux rope with themore » higher twist was found to expand with an approximately constant field twist. In addition, the helicity flux maps deduced from the HMI magnetograms show that some helicity is injected into the overlying magnetic arcade, but no significant helicity is injected into the flux ropes. Accordingly, we suggest that the highly twisted flux rope became kink unstable when the instability threshold declined with the expansion of the flux rope.« less

Authors:
; ; ; ; ;  [1]
  1. Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China)
Publication Date:
OSTI Identifier:
22522406
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 805; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ERUPTION; EXTRAPOLATION; FILAMENTS; HELICITY; IMAGES; KINK INSTABILITY; MAGNETIC FIELDS; MAGNETIC FLUX; NONLINEAR PROBLEMS; SUN; TELESCOPES

Citation Formats

Bi, Yi, Jiang, Yunchun, Yang, Jiayan, Xiang, Yongyuan, Cai, Yunfang, and Liu, Weiwei, E-mail: biyi@ynao.ac.cn. PARTIAL ERUPTION OF A FILAMENT WITH TWISTING NON-UNIFORM FIELDS. United States: N. p., 2015. Web. doi:10.1088/0004-637X/805/1/48.
Bi, Yi, Jiang, Yunchun, Yang, Jiayan, Xiang, Yongyuan, Cai, Yunfang, & Liu, Weiwei, E-mail: biyi@ynao.ac.cn. PARTIAL ERUPTION OF A FILAMENT WITH TWISTING NON-UNIFORM FIELDS. United States. doi:10.1088/0004-637X/805/1/48.
Bi, Yi, Jiang, Yunchun, Yang, Jiayan, Xiang, Yongyuan, Cai, Yunfang, and Liu, Weiwei, E-mail: biyi@ynao.ac.cn. Wed . "PARTIAL ERUPTION OF A FILAMENT WITH TWISTING NON-UNIFORM FIELDS". United States. doi:10.1088/0004-637X/805/1/48.
@article{osti_22522406,
title = {PARTIAL ERUPTION OF A FILAMENT WITH TWISTING NON-UNIFORM FIELDS},
author = {Bi, Yi and Jiang, Yunchun and Yang, Jiayan and Xiang, Yongyuan and Cai, Yunfang and Liu, Weiwei, E-mail: biyi@ynao.ac.cn},
abstractNote = {The eruption of a filament in a kinklike fashion is often regarded as a signature of kink instability. However, the kink instability threshold for the filament’s magnetic structure is not widely understood. Using Hα observations from the New Vacuum Solar Telescope, we present a partial eruptive filament. During the eruption, the filament thread appeared to split from its middle and to break out in a kinklike fashion. In this period, the remaining filament material stayed below and erupted without the kinking motion later on. The coronal magnetic field lines associated with the filament are obtained from nonlinear force-free field extrapolations using the twelve-minute-cadence vector magnetograms of the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory. We studied the extrapolated field lines passing through the magnetic dips which are in good agreement with the observed filament. The field lines are non-uniformly twisted and appear to be composed of two twisted flux ropes winding around each other. One of them has a higher twist than the other, and the flux rope with the higher twist has its dips aligned with the kinking eruptive thread at the beginning of its eruption. Before the eruption, moreover, the flux rope with the higher twist was found to expand with an approximately constant field twist. In addition, the helicity flux maps deduced from the HMI magnetograms show that some helicity is injected into the overlying magnetic arcade, but no significant helicity is injected into the flux ropes. Accordingly, we suggest that the highly twisted flux rope became kink unstable when the instability threshold declined with the expansion of the flux rope.},
doi = {10.1088/0004-637X/805/1/48},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 805,
place = {United States},
year = {2015},
month = {5}
}