Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. III. Twist Number Method

	Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. III. Twist Number Method
	Guo, Y.1,2; Pariat, E.3; Valori, G.4; Anfinogentov, S.5; Chen, F.6; Georgoulis, M. K.7; Liu, Y.8; Moraitis, K.3,7; Thalmann, J. K.9; Yang, S.10
刊名	ASTROPHYSICAL JOURNAL
	2017-05-01
卷号	840 期号:1
关键词	Sun: activity Sun: corona Sun: magnetic fields
英文摘要	We study the writhe, twist, and magnetic helicity of different magnetic flux ropes, based on models of the solar coronal magnetic field structure. These include an analytical force-free Titov-Demoulin equilibrium solution, nonforce-free magnetohydrodynamic simulations, and nonlinear force-free magnetic field models. The geometrical boundary of the magnetic flux rope is determined by the quasi-separatrix layer and the bottom surface, and the axis curve of the flux rope is determined by its overall orientation. The twist is computed by the Berger-Prior formula, which is suitable for arbitrary geometry and both force-free and non-force-free models. The magnetic helicity is estimated by the twist multiplied by the square of the axial magnetic flux. We compare the obtained values with those derived by a finite volume helicity estimation method. We find that the magnetic helicity obtained with the twist method agrees with the helicity carried by the purely current-carrying part of the field within uncertainties for most test cases. It is also found that the current-carrying part of the model field is relatively significant at the very location of the magnetic flux rope. This qualitatively explains the agreement between the magnetic helicity computed by the twist method and the helicity contributed purely by the current-carrying magnetic field.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	QUASI-SEPARATRIX LAYERS ; CORONAL MASS EJECTIONS ; ACTIVE-REGION ; FLUX ROPES ; VECTOR MAGNETOGRAMS ; ERUPTION TOPOLOGIES ; EVOLUTION ; ENERGY ; FLARE ; CONFIGURATIONS
收录类别	SCI
语种	英语
WOS记录号	WOS:000400915200004
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/8776]
专题	国家天文台_太阳物理研究部
作者单位	1.Nanjing Univ, Minist Educ, Sch Astron & Space Sci, Nanjing 210023, Jiangsu, Peoples R China 2.Nanjing Univ, Minist Educ, Key Lab Modern Astron & Astrophys, Nanjing 210023, Jiangsu, Peoples R China 3.UPMC Univ Paris 06, Univ Paris Diderot, Sorbonne Univ, LESIA,Observ Paris,PSL Res Univ,CNRS,Sorbon Paris, F-92190 Meudon, France 4.Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England 5.Inst Solar Terr Phys SB RAS, POB 291,Lermontov St,126a, Irkutsk 664033, Russia 6.Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany 7.Acad Athens, Res Ctr Astron & Appl Math, 4 Soranou Efesiou St, Athens 11527, Greece 8.Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA 9.Karl Franzens Univ Graz, Inst Phys, Univ Pl 5-2, A-8010 Graz, Austria 10.Chinese Acad Sci, Key Lab Solar Act, Natl Astron Observ, Beijing 100012, Peoples R China
推荐引用方式 GB/T 7714	Guo, Y.,Pariat, E.,Valori, G.,et al. Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. III. Twist Number Method[J]. ASTROPHYSICAL JOURNAL,2017,840(1).
APA	Guo, Y..,Pariat, E..,Valori, G..,Anfinogentov, S..,Chen, F..,...&Yang, S..(2017).Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. III. Twist Number Method.ASTROPHYSICAL JOURNAL,840(1).
MLA	Guo, Y.,et al."Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. III. Twist Number Method".ASTROPHYSICAL JOURNAL 840.1(2017).