Evolution of Relative Magnetic Helicity: Method of Computation and Its Application to a Simulated Solar Corona above an Active Region

	Evolution of Relative Magnetic Helicity: Method of Computation and Its Application to a Simulated Solar Corona above an Active Region
	Yang, Shangbin1,2 ; Buechner, Joerg 2; Santos, Jean Carlo 3; Zhang, Hongqi1
刊名	SOLAR PHYSICS
	2013-04-01
卷号	283 期号:2 页码:369-382
关键词	Magnetic helicity MHD simulation Solar magnetic fields
英文摘要	For a better understanding of solar magnetic field evolution it is appropriate to evaluate the magnetic helicity based on observations and to compare it with numerical simulation results. We have developed a method for calculating the vector potential of a magnetic field given in a finite volume; the method requires the magnetic flux to be balanced on all the side boundaries of the considered volume. Our method uses a fast Laplace/Poisson solver to obtain the vector potentials for a given magnetic field and for the corresponding potential (current-free) field. This allows an efficient calculation of the relative magnetic helicity in a finite 3D volume. We tested our approach on a theoretical model (Low and Lou, Astrophys. J. 352, 343, 1990) and also applied our method to the magnetic field above active region NOAA 8210 obtained by a photospheric-data-driven MHD model. We found that the amount of accumulated relative magnetic helicity coincides well with the relative helicity inflow through the boundaries in the ideal and non-ideal cases. The temporal evolution of relative magnetic helicity is consistent with that of magnetic energy. The maximum value of normalized helicity, H (m)/I broken vertical bar(2)=0.0298, is reached just before a drastic energy release by magnetic reconnection. This value is close to the corresponding value inferred from the formula that connects the magnetic flux and the accumulated magnetic helicity based on the observations of solar active regions.
收录类别	SCI
语种	英语
WOS记录号	WOS:000316265100009
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/5824]
专题	国家天文台_太阳物理研究部
作者单位	1.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China 2.Max Planck Inst Solar Syst Res, D-37191 Katlenburg Lindau, Germany 3.Univ Brasilia, Lab Plasmas, Inst Fis, Brasilia, DF, Brazil
推荐引用方式 GB/T 7714	Yang, Shangbin,Buechner, Joerg,Santos, Jean Carlo,et al. Evolution of Relative Magnetic Helicity: Method of Computation and Its Application to a Simulated Solar Corona above an Active Region[J]. SOLAR PHYSICS,2013,283(2):369-382.
APA	Yang, Shangbin,Buechner, Joerg,Santos, Jean Carlo,&Zhang, Hongqi.(2013).Evolution of Relative Magnetic Helicity: Method of Computation and Its Application to a Simulated Solar Corona above an Active Region.SOLAR PHYSICS,283(2),369-382.
MLA	Yang, Shangbin,et al."Evolution of Relative Magnetic Helicity: Method of Computation and Its Application to a Simulated Solar Corona above an Active Region".SOLAR PHYSICS 283.2(2013):369-382.