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The effect of line damping, magneto-optics and parasitic light on the derivation of sunspot vector magnetic fieldsThe least square fitting of Stokes observations of sunspots using a Milne-Eddington-Unno model appears to lead, in many circumstances, to various inconsistencies such as anomalously large doppler widths and, hence, small magnetic fields which are significantly below those inferred solely from the Zeeman splitting in the intensity profile. It is found that the introduction of additional physics into the model such as the inclusion of damping wings and magneto-optic birefrigence significantly improves the fit to Stokes parameters. Model fits excluding the intensity profile, i.e., of both magnitude as well as spectral shape of the polarization parameters alone, suggest that parasitic light in the intensity profile may also be a source of inconsistencies. The consequences of the physical changes on the vector properties of the field derived from the Fe I lambda 6173 line for the 17 November 1975 spot as well as on the thermodynamic state are discussed. A Doppler width delta lambda (D) - 25mA is bound to be consistent with a low spot temperature and microturbulence, and a damping constant of a = 0.2.
Document ID
19850021583
Document Type
Conference Paper
Authors
Skumanich, A. (National Center for Atmospheric Research Boulder, CO, United States)
Lites, B. W. (Sacramento Peak Observatory Sunspot, N. Mex., United States)
Date Acquired
August 12, 2013
Publication Date
May 1, 1985
Publication Information
Publication: NASA. Marshall Space Flight Center Meas. of Solar Vector Magnetic Fields
Subject Category
SOLAR PHYSICS
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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