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Measurements of solar magnetic fields by Fourier transform techniques. II - Saturated and blended linesFourier techniques have been exhaustively calibrated using Unno's (1956) results for the absorption profile of a simple Zeeman triplet. If a simple transformation is applied to the normalized line depths, then magnetic-field strengths and inclination angles can be measured very accurately from noisy saturated line profiles. Systematic errors caused by saturation effects can be estimated and reduced by varying one parameter. When a significant fraction of the line profile is unsplit and unpolarized, large errors may be made in measurements of low fields, unless the line is sufficiently weak. For a weak line, a vertical field of 1600 gauss can be measured to 10% accuracy even when 70% of the line profile is stray light. These stray-light errors are troublesome in measuring fields of gaps and pores but not sunspots. Numerical results of the error analysis are presented graphically.
Document ID
19770036057
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Tarbell, T. D.
(Lockheed Missiles and Space Co. Palo Alto, CA, United States)
Title, A. M.
(Lockheed Research Laboratories Palo Alto, Calif., United States)
Date Acquired
August 9, 2013
Publication Date
April 1, 1976
Publication Information
Publication: Solar Physics
Volume: 47
Subject Category
Solar Physics
Accession Number
77A18909
Funding Number(s)
CONTRACT_GRANT: NAS8-30628
Distribution Limits
Public
Copyright
Other

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