A new and fast way to reconstruct a nonlinear force-free field in the solar corona

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	A new and fast way to reconstruct a nonlinear force-free field in the solar corona
	Song, M. T.; Fang, C.; Tang, Y. H.; Wu, S. T.; Zhang, Y. A.
刊名	ASTROPHYSICAL JOURNAL
	2006-10-01
卷号	649 期号:2 页码:1084-1092
关键词	MHD Sun : corona Sun : magnetic fields
ISSN号	0004-637X
英文摘要	We reexamine the method of upward integration of a nonlinear force-free field (NFFF), which is, as is well known, an ill-posed problem. It can be modified to a well-posed one by the following means: instead of using finite difference to express partial derivatives, we use smooth continuous functions to approach magnetic field values, write down three field components consisting of amplitude functions multiplying morphology functions, and reduce four basic NFFF equations to ordinary differential ones. They are then solved in an asymptotic manner (zeroth-order, first-order, etc.). Considering the physical meaning of alpha, we found a self-consistent compatibility condition for the boundary values. Furthermore, a computation algorithm is proposed, similar to the usual time-dependent two-dimensional MHD simulation scheme. This algorithm is steady and robust against the noise in the magnetic field ( in particular, the transverse field) measurement and is able to deal with concentrated photospheric currents. The algorithm runs very fast on an ordinary PC and lasts only 6 minutes for the 80 x 60 (x x y) mesh up to a height of 80 (=216,000 km similar to 0.3 R-circle dot). So it provides a powerful tool for solar scientists to analyze the magnetic field properties of solar active regions and to make predictions of solar activity.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	FREE MAGNETIC-FIELD ; VECTOR MAGNETOGRAPH DATA ; NON-CONSTANT-ALPHA ; COMPUTATION ; CODE
收录类别	SCI
语种	英语
WOS记录号	WOS:000240854200047
公开日期	2012-02-07
内容类型	期刊论文
源URL	[http://159.226.72.40/handle/332002/3584]
专题	紫金山天文台_太阳高能及相关物理过程研究团组
作者单位	1.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China 2.Nanjing Univ, Dept Astron, Nanjing 210093, Peoples R China 3.Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA 4.Univ Alabama, Dept Mech & Aerosp Engn, Huntsville, AL 35899 USA
推荐引用方式 GB/T 7714	Song, M. T.,Fang, C.,Tang, Y. H.,et al. A new and fast way to reconstruct a nonlinear force-free field in the solar corona[J]. ASTROPHYSICAL JOURNAL,2006,649(2):1084-1092.
APA	Song, M. T.,Fang, C.,Tang, Y. H.,Wu, S. T.,&Zhang, Y. A..(2006).A new and fast way to reconstruct a nonlinear force-free field in the solar corona.ASTROPHYSICAL JOURNAL,649(2),1084-1092.
MLA	Song, M. T.,et al."A new and fast way to reconstruct a nonlinear force-free field in the solar corona".ASTROPHYSICAL JOURNAL 649.2(2006):1084-1092.