Projection effects on physical parameters obtained from solar vector magnetograms

CORC > 紫金山天文台 > 中国科学院紫金山天文台 > 太阳高能及相关物理过程研究团组

	Projection effects on physical parameters obtained from solar vector magnetograms
	Li, H
刊名	CHINESE JOURNAL OF ASTRONOMY AND ASTROPHYSICS
	2002-04-01
卷号	2 期号:2 页码:174-182
关键词	Sun : magnetic fields Sun : activity Sun : photosphere
英文摘要	Projection effects in Huairou solar vector magnetograms are corrected by transferring or mapping the observed vector magnetogram in the image plane to the heliographic plane (planar correction) and to the heliospheric coordinate system (spherical correction). The magnetograms after the correction are considerably different. The planar correction and the spherical correction lead to slightly different magnetic configurations, especially when the active region involved is far from the disk center. We also discuss the effects of the corrections on magnetic activity parameters, such as magnetic shear, current helicity, etc. It is shown that the neutral line is obviously distorted after the mapping. The mapping generally decreases the average shear angle on the neutral line by several degrees when the active region is in the eastern hemisphere, and increases it when in the western hemisphere. In most of the cases studied, the correction reduces the current helicity imbalance, and sometimes even changes its sign. It is found that the current helicity imbalance may change its sign in its evolution when there are apparent fluxes emerging from the lower photosphere. The corrections increase the noise level of B-z greatly, and decrease the noise level of B-t slightly. The accuracy of the magnetic field measurement at Huairou is estimated to be better than 20 G and 150 G for the longitudinal and the transverse component, respectively.
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]	MAGNETIC SHEAR ; CURRENT HELICITY ; ACTIVE-REGION ; CLASS FLARES ; FIELD ; EVOLUTION ; SOLAR-CYCLE-22
收录类别	SCI
语种	英语
WOS记录号	WOS:000175150900011
公开日期	2013-01-29
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/7928]
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.Acad Sinica, Natl Astron Observ, Beijing 100012, Peoples R China
推荐引用方式 GB/T 7714	Li, H. Projection effects on physical parameters obtained from solar vector magnetograms[J]. CHINESE JOURNAL OF ASTRONOMY AND ASTROPHYSICS,2002,2(2):174-182.
APA	Li, H.(2002).Projection effects on physical parameters obtained from solar vector magnetograms.CHINESE JOURNAL OF ASTRONOMY AND ASTROPHYSICS,2(2),174-182.
MLA	Li, H."Projection effects on physical parameters obtained from solar vector magnetograms".CHINESE JOURNAL OF ASTRONOMY AND ASTROPHYSICS 2.2(2002):174-182.