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| Paper: |
Polarized Line Formation with Angle-Dependent Partial Frequency Redistribution |
| Volume: |
489, Solar Polarization 7 |
| Page: |
197 |
| Authors: |
Sampoorna, M. |
| Abstract: |
The linear polarization of spectral lines seen in the solar limb observations
is created by the scattering of the anisotropic radiation field by atoms
and molecules. The partial frequency redistribution (PRD) effects in line
scattering are necessary ingredients for interpreting the linear
polarization observed in strong resonance lines. This polarization is
sensitive to the form of the PRD function used in the polarized line
transfer equation. The use of angle-averaged PRD function is quite common
in the literature on polarized transfer, as it greatly reduces the
computing efforts. In this paper we present our recent work on the
importance of the angle-dependent PRD in polarized line transfer. First we
present a brief historical background on polarized transfer with
angle-dependent PRD. To simplify the numerical work needed to handle
angle-dependent PRD function a Stokes vector decomposition technique was
developed by Frisch (2009, 2010).
After briefly recalling this technique,
we present two numerical methods developed to solve
the polarized line transfer with angle-dependent PRD. These are (1)
polarized accelerated lambda iteration method and (2) the scattering
expansion method. Through illustrative examples, we show that while
angle-dependent effects are somewhat less important for scattering
polarization in the absence of magnetic fields, they play an important
role in the presence of a weak magnetic field. |
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