Evolution of relative magnetic helicity New boundary conditions for the vector potential

doi:10.1051/0004-6361/201628108

CORC > 国家天文台 > 中国科学院国家天文台

	Evolution of relative magnetic helicity New boundary conditions for the vector potential
	Yang, Shangbin 2,3,4; Buechner, Joerg 3; Skala, Jan 1,3,5; Zhang, Hongqi 2
刊名	ASTRONOMY & ASTROPHYSICS
	2018-05-25
卷号	613 页码:7
关键词	Sun: magnetic fields Sun: corona magnetohydrodynamics (MHD)
ISSN号	1432-0746
DOI	10.1051/0004-6361/201628108
英文摘要	Context. For a better understanding of the dynamics of the solar corona, it is important to analyse the evolution of the helicity of the magnetic field. Since the helicity cannot be directly determined by observations, we have recently proposed a method to calculate the relative magnetic helicity in a finite volume for a given magnetic field, which however required the flux to be balanced separately on all the sides of the considered volume. Aims. We developed a scheme to obtain the vector potential in a volume without the above restriction at the boundary. We studied the dissipation and escape of relative magnetic helicity from an active region. Methods. In order to allow finite magnetic fluxes through the boundaries, a Coulomb gauge was constructed that allows for global magnetic flux balance. The property of sinusoidal function was used to obtain the vector potentials at the 12 edges of the considered rectangular volume extending above an active region. We tested and verified our method in a theoretical fore-free magnetic field model. Results. We applied the new method to the former calculation data and found a difference of less than 1.2%. We also applied our method to the magnetic field above active region NOAA 11429 obtained by a new photospheric-data-driven magnetohydrodynamics (MHD) model code GOEMHD3. We analysed the magnetic helicity evolution in the solar corona using our new method. We find that the normalized magnetic helicity (H-1 Phi(2)) is equal to 0.038 when fast magnetic reconnection is triggered. This value is comparable to the previous value (0.029) in the MHD simulations when magnetic reconnection happened and the observed normalized magnetic helicity (0.036) from the eruption of newly emerging active regions. We find that only 8% of the accumulated magnetic helicity is dissipated after it is injected through the bottom boundary. This is in accordance with theWoltjer conjecture. Only 2% of the magnetic helicity injected from the bottom boundary escapes through the corona. This is consistent with the observation of magnetic clouds, which could take magnetic helicity into the interplanetary space. In the case considered here, several halo coronal mass ejections (CMEs) and two X-class solar flares originate from this active region.
资助项目	National Natural Science Foundation of China[11427901] ; National Natural Science Foundation of China[10921303] ; National Natural Science Foundation of China[11673033] ; National Natural Science Foundation of China[U1731113] ; National Natural Science Foundation of China[11611530679] ; National Natural Science Foundation of China[11573037] ; Strategic Priority Research Program of Chinese Academy of Sciences[XDB09040200] ; Strategic Priority Research Program of Chinese Academy of Sciences[XDA15010700] ; Max-Planck Society Interinstitutional Research Initiative Turbulent transport and ion heating, reconnection, and electron acceleration in solar and fusion plasmas[MIF-IF-A-AERO8047] ; Max-Planck-Princeton Center for Plasma Physics[PS AERO 8003] ; ISSI International Team on Magnetic Helicity estimations in models and observations of the solar magnetic field
WOS关键词	CORONAL MASS EJECTIONS ; ACTIVE REGIONS ; SOLAR CORONA ; FLUX ROPES ; FIELDS ; ACCUMULATION ; CONFINEMENT ; MODELS ; FLARES
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	EDP SCIENCES S A
WOS记录号	WOS:000432981300002
资助机构	National Natural Science Foundation of China ; National Natural Science Foundation of China ; Strategic Priority Research Program of Chinese Academy of Sciences ; Strategic Priority Research Program of Chinese Academy of Sciences ; Max-Planck Society Interinstitutional Research Initiative Turbulent transport and ion heating, reconnection, and electron acceleration in solar and fusion plasmas ; Max-Planck Society Interinstitutional Research Initiative Turbulent transport and ion heating, reconnection, and electron acceleration in solar and fusion plasmas ; Max-Planck-Princeton Center for Plasma Physics ; Max-Planck-Princeton Center for Plasma Physics ; ISSI International Team on Magnetic Helicity estimations in models and observations of the solar magnetic field ; ISSI International Team on Magnetic Helicity estimations in models and observations of the solar magnetic field ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Strategic Priority Research Program of Chinese Academy of Sciences ; Strategic Priority Research Program of Chinese Academy of Sciences ; Max-Planck Society Interinstitutional Research Initiative Turbulent transport and ion heating, reconnection, and electron acceleration in solar and fusion plasmas ; Max-Planck Society Interinstitutional Research Initiative Turbulent transport and ion heating, reconnection, and electron acceleration in solar and fusion plasmas ; Max-Planck-Princeton Center for Plasma Physics ; Max-Planck-Princeton Center for Plasma Physics ; ISSI International Team on Magnetic Helicity estimations in models and observations of the solar magnetic field ; ISSI International Team on Magnetic Helicity estimations in models and observations of the solar magnetic field ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Strategic Priority Research Program of Chinese Academy of Sciences ; Strategic Priority Research Program of Chinese Academy of Sciences ; Max-Planck Society Interinstitutional Research Initiative Turbulent transport and ion heating, reconnection, and electron acceleration in solar and fusion plasmas ; Max-Planck Society Interinstitutional Research Initiative Turbulent transport and ion heating, reconnection, and electron acceleration in solar and fusion plasmas ; Max-Planck-Princeton Center for Plasma Physics ; Max-Planck-Princeton Center for Plasma Physics ; ISSI International Team on Magnetic Helicity estimations in models and observations of the solar magnetic field ; ISSI International Team on Magnetic Helicity estimations in models and observations of the solar magnetic field ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Strategic Priority Research Program of Chinese Academy of Sciences ; Strategic Priority Research Program of Chinese Academy of Sciences ; Max-Planck Society Interinstitutional Research Initiative Turbulent transport and ion heating, reconnection, and electron acceleration in solar and fusion plasmas ; Max-Planck Society Interinstitutional Research Initiative Turbulent transport and ion heating, reconnection, and electron acceleration in solar and fusion plasmas ; Max-Planck-Princeton Center for Plasma Physics ; Max-Planck-Princeton Center for Plasma Physics ; ISSI International Team on Magnetic Helicity estimations in models and observations of the solar magnetic field ; ISSI International Team on Magnetic Helicity estimations in models and observations of the solar magnetic field
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/21702]
专题	中国科学院国家天文台
通讯作者	Yang, Shangbin
作者单位	1.Univ JE Purkyne, Usti Nad Labem 40096, Czech Republic 2.Chinese Acad Sci, Key Lab Solar Act, Natl Astron Observ, Beijing 100012, Peoples R China 3.Max Planck Inst Solar Syst Res, D-37077 Gottingen, Germany 4.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 5.Czech Acad Sci, Astron Inst, Ondrejov 25165, Czech Republic
推荐引用方式 GB/T 7714	Yang, Shangbin,Buechner, Joerg,Skala, Jan,et al. Evolution of relative magnetic helicity New boundary conditions for the vector potential[J]. ASTRONOMY & ASTROPHYSICS,2018,613:7.
APA	Yang, Shangbin,Buechner, Joerg,Skala, Jan,&Zhang, Hongqi.(2018).Evolution of relative magnetic helicity New boundary conditions for the vector potential.ASTRONOMY & ASTROPHYSICS,613,7.
MLA	Yang, Shangbin,et al."Evolution of relative magnetic helicity New boundary conditions for the vector potential".ASTRONOMY & ASTROPHYSICS 613(2018):7.