Nonlinear calibration of vector magnetograms by the video vector magnetograph at Huairou

	Nonlinear calibration of vector magnetograms by the video vector magnetograph at Huairou
	Ruan, Guiping; Zhang, Hongqi
刊名	NEW ASTRONOMY
	2006-12-01
卷号	12 期号:3 页码:215-223
关键词	sun : nonlinear calibration sun : magnetic fields
英文摘要	We compare the results of two calibration methods for deriving a photospheric vector magnetogram, as applied to the Fei 5324.19 angstrom line. The first method ignores the dependence of its calibration coefficients on the inclination angle. The second method is a multi-iteration, nonlinear calibration technique developed by [M.J. Hagyard, J.I. Kineke, Solar Phys. 158 (1995) 11], which allows the polarization signals to depend on both field strength and inclination angle. We compare the relationship between the derived solar magnetic field and the Stokes parameters under both methods. We find that the circular polarization signal of the Fei 5324.19 A line is linearly proportional to the longitudinal strength, B(L), when the field strength ranges from 0 to 1000 Gauss. For B(L) > 1000 G and inclination angles ranging from 30 degrees to 90 degrees, deviation from linearity is significant. For the transverse field, B(T), the assumption of linearity only holds for 0 < B(T) < 300 G. In contrast to the former method of calibration, the improved calibration method accounts for the nonlinear relationship between polarization signals and the magnetic field strength. Using [A. Skumanich, in: J.H. Thomas and N.O. Weiss (Eds.), Sunspots: Theory and Observations. Kluwer, Dordrecht, 1992, p. 121] dipole field model., we show that the Fei 5324.19 angstrom line has more linear property than the Fei 6302.5 angstrom line. (c) 2006 Elsevier B.V. All rights reserved.
收录类别	SCI
语种	英语
WOS记录号	WOS:000243175900007
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/7086]
专题	国家天文台_太阳物理研究部
作者单位	Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
推荐引用方式 GB/T 7714	Ruan, Guiping,Zhang, Hongqi. Nonlinear calibration of vector magnetograms by the video vector magnetograph at Huairou[J]. NEW ASTRONOMY,2006,12(3):215-223.
APA	Ruan, Guiping,&Zhang, Hongqi.(2006).Nonlinear calibration of vector magnetograms by the video vector magnetograph at Huairou.NEW ASTRONOMY,12(3),215-223.
MLA	Ruan, Guiping,et al."Nonlinear calibration of vector magnetograms by the video vector magnetograph at Huairou".NEW ASTRONOMY 12.3(2006):215-223.