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Title: | Polarized Line Formation in Multi-dimensional Media. V. Effects of Angle-dependent Partial Frequency Redistribution |
Authors: | Anusha, L. S Nagendra, K. N |
Keywords: | Line: formation Magnetic fields Polarization Radiative transfer Scattering Sun: atmosphere |
Issue Date: | 10-Feb-2012 |
Publisher: | IOP Publishing |
Citation: | The Astrophysical Journal, Vol. 746, No. 1 , 84 |
Abstract: | The solution of polarized radiative transfer equation with angle-dependent (AD) partial frequency redistribution (PRD) is a challenging problem. Modeling the observed, linearly polarized strong resonance lines in the solar spectrum often requires the solution of the AD line transfer problems in one-dimensional or multi-dimensional (multi-D) geometries. The purpose of this paper is to develop an understanding of the relative importance of the AD PRD effects and the multi-D transfer effects and particularly their combined influence on the line polarization. This would help in a quantitative analysis of the second solar spectrum (the linearly polarized spectrum of the Sun). We consider both non-magnetic and magnetic media. In this paper we reduce the Stokes vector transfer equation to a simpler form using a Fourier decomposition technique for multi-D media. A fast numerical method is also devised to solve the concerned multi-D transfer problem. The numerical results are presented for a two-dimensional medium with a moderate optical thickness (effectively thin) and are computed for a collisionless frequency redistribution. We show that the AD PRD effects are significant and cannot be ignored in a quantitative fine analysis of the line polarization. These effects are accentuated by the finite dimensionality of the medium (multi-D transfer). The presence of magnetic fields (Hanle effect) modifies the impact of these two effects to a considerable extent. |
Description: | Open Access |
URI: | http://hdl.handle.net/2248/5685 |
Appears in Collections: | IIAP Publications |
Files in This Item:
File | Description | Size | Format | |
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Polarized Line Formation in Multi-dimensional Media. V.pdf | Open Access | 1.22 MB | Adobe PDF | ![]() View/Open |
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