High-resolution Observations of Flares in an Arch Filament System

	High-resolution Observations of Flares in an Arch Filament System
	Su, Yingna; Liu, Rui; Li, Shangwei; Cao, Wenda; Ahn, Kwangsu; Ji, Haisheng
刊名	ASTROPHYSICAL JOURNAL
	2018
卷号	855 期号:2 页码:77
英文摘要	We study five sequential solar flares (SOL2015-08-07) occurring in Active Region 12396 observed with the Goode Solar Telescope (GST) at the Big Bear Solar Observatory, complemented by Interface Region Imaging Spectrograph and SDO observations. The main flaring region is an arch filament system (AFS) consisting of multiple bundles of dark filament threads enclosed by semicircular flare ribbons. We study the magnetic configuration and evolution of the active region by constructing coronal magnetic field models based on SDO/HMI magnetograms using two independent methods, i.e., the nonlinear force-free field (NLFFF) extrapolation and the flux rope insertion method. The models consist of multiple flux ropes with mixed signs of helicity, i.e., positive (negative) in the northern (southern) region, which is consistent with the GST observations of multiple filament bundles. The footprints of quasi-separatrix layers (QSLs) derived from the extrapolated NLFFF compare favorably with the observed flare ribbons. An interesting double-ribbon fine structure located at the east border of the AFS is consistent with the fine structure of the QSL's footprint. Moreover, magnetic field lines traced along the semicircular footprint of a dome-like QSL surrounding the AFS are connected to the regions of significant helicity and Poynting flux injection. The maps of magnetic twist show that positive twist became dominant as time progressed, which is consistent with the injection of positive helicity before the flares. We hence conclude that these circular shaped flares are caused by 3D magnetic reconnection at the QSLs associated with the AFS possessing mixed signs of helicity.
语种	英语
WOS记录号	WOS:000431812800004
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/18057]
专题	中国科学院紫金山天文台
推荐引用方式 GB/T 7714	Su, Yingna,Liu, Rui,Li, Shangwei,et al. High-resolution Observations of Flares in an Arch Filament System[J]. ASTROPHYSICAL JOURNAL,2018,855(2):77.
APA	Su, Yingna,Liu, Rui,Li, Shangwei,Cao, Wenda,Ahn, Kwangsu,&Ji, Haisheng.(2018).High-resolution Observations of Flares in an Arch Filament System.ASTROPHYSICAL JOURNAL,855(2),77.
MLA	Su, Yingna,et al."High-resolution Observations of Flares in an Arch Filament System".ASTROPHYSICAL JOURNAL 855.2(2018):77.