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Modeling the center-to-limb variation of the Ca i 4227 Å line using FCHHT models

Published online by Cambridge University Press:  24 July 2015

H. D. Supriya
Affiliation:
Indian Institute of Astrophysics, Bangalore 560034, India email: hdsupriya@iiap.res.in, smithahn@iiap.res.in, knn@iiap.res.in, ravindra@iiap.res.in
H. N. Smitha
Affiliation:
Indian Institute of Astrophysics, Bangalore 560034, India email: hdsupriya@iiap.res.in, smithahn@iiap.res.in, knn@iiap.res.in, ravindra@iiap.res.in
K. N. Nagendra
Affiliation:
Indian Institute of Astrophysics, Bangalore 560034, India email: hdsupriya@iiap.res.in, smithahn@iiap.res.in, knn@iiap.res.in, ravindra@iiap.res.in
J. O. Stenflo
Affiliation:
Institute of Astronomy, ETH Zurich, CH-8093 Zurich, Switzerland email: stenflo@astro.phys.ethz.ch Istituto Ricerche Solari Locarno, Via Patocchi, CH-6605 Locarno-Monti, Switzerland email: mbianda@irsol.ch, ramelli@irsol.ch
M. Bianda
Affiliation:
Istituto Ricerche Solari Locarno, Via Patocchi, CH-6605 Locarno-Monti, Switzerland email: mbianda@irsol.ch, ramelli@irsol.ch
B. Ravindra
Affiliation:
Indian Institute of Astrophysics, Bangalore 560034, India email: hdsupriya@iiap.res.in, smithahn@iiap.res.in, knn@iiap.res.in, ravindra@iiap.res.in
R. Ramelli
Affiliation:
Istituto Ricerche Solari Locarno, Via Patocchi, CH-6605 Locarno-Monti, Switzerland email: mbianda@irsol.ch, ramelli@irsol.ch
L. S. Anusha
Affiliation:
Max Planck Institut für Sonnesystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen, Germany email: bhasari@mps.mpg.de
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Abstract

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The Ca i 4227 Å is a chromospheric line exhibiting the largest degree of linear polarization near the limb, in the visible spectrum of the Sun. Modeling the observations of the center-to-limb variations (CLV) of different lines in the Second Solar Spectrum helps to sample the height dependence of the magnetic field, as the observations made at different lines of sight sample different heights in the solar atmosphere. Supriya et al. (2014) attempted to simultaneously model the CLV of the (I, Q/I) spectra of the Ca i 4227 Å line using the standard 1-D FAL model atmospheres. They found that the standard FAL model atmospheres and also any appropriate combination of them, fail to simultaneously fit the observed Stokes (I, Q/I) profiles at all the limb distances (μ) satisfying at the same time all the observational constraints. This failure of 1-D modeling approach can probably be overcome by using multi-dimensional modeling which is computationally expensive. To eliminate an even wider choice of 1-D models, we attempt here to simultaneously model the CLV of the (I, Q/I) spectra using the FCHHT solar model atmospheres which are updated and recent versions of the FAL models. The details of our modeling efforts and the results are presented.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2015 

References

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