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The influence of sunspot canopies on magnetic inclination measurements in solar plages

✍ Scribed by Sami K. Solanki; Wolfgang Finsterle; Isabelle Rüedi

Publisher
Springer
Year
1996
Tongue
English
Weight
695 KB
Volume
164
Category
Article
ISSN
0038-0938

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✦ Synopsis

Sunspots are known to have large, low-lying magnetic canopies, i.e. horizontal magnetic fields overlying a field-free medium, that cover substantial fractions of active region plage. In this paper we consider the influence of such canopies on the inclination of plage magnetic fields. We find that for observations in spectral lines like 5250.2/~ the neglect of a sunspot canopy when determining magnetic inclination angles of plage fields can introduce errors exceeding 5-10 ~ . This is particularly true if the observations do not have high spatial resolution. Thus this effect may explain some of the measurements of substantially inclined fields in solar plages. Furthermore we find that the Fe I 15648 line is far superior in giving correct flux-tube inclinations in the presence of a sunspot magnetic canopy. Finally, the inversion of full Stokes profiles is shown to produce more reliable results than results obtained by considering only ratios of individual Stokes profile parameters.

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