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Polarized line formation with lower-level polarization and partial frequency redistribution

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dc.contributor.author Supriya, H. D
dc.contributor.author Sampoorna, M
dc.contributor.author Nagendra, K. N
dc.contributor.author Stenflo, J. O
dc.contributor.author Ravindra, B
dc.date.accessioned 2020-11-17T14:02:31Z
dc.date.available 2020-11-17T14:02:31Z
dc.date.issued 2016-09-10
dc.identifier.citation The Astrophysical Journal, Vol. 828, No. 2, 84 en_US
dc.identifier.issn 1538-4357
dc.identifier.uri http://prints.iiap.res.in/handle/2248/7104
dc.description Restricted Access © The American Astronomical Society http://dx.doi.org/10.3847/0004-637X/828/2/84 en_US
dc.description.abstract In the well-established theories of polarized line formation with partial frequency redistribution (PRD) for a two-level and two-term atom, it is generally assumed that the lower level of the scattering transition is unpolarized. However, the existence of unexplained spectral features in some lines of the Second Solar Spectrum points toward a need to relax this assumption. There exists a density matrix theory that accounts for the polarization of all the atomic levels, but it is based on the flat-spectrum approximation (corresponding to complete frequency redistribution). In the present paper we propose a numerical algorithm to solve the problem of polarized line formation in magnetized media, which includes both the effects of PRD and the lower level polarization (LLP) for a two-level atom. First we derive a collisionless redistribution matrix that includes the combined effects of the PRD and the LLP. We then solve the relevant transfer equation using a two-stage approach. For illustration purposes, we consider two case studies in the non-magnetic regime, namely, the J a = 1, J b = 0 and J a = J b = 1, where J a and J b represent the total angular momentum quantum numbers of the lower and upper states, respectively. Our studies show that the effects of LLP are significant only in the line core. This leads us to propose a simplified numerical approach to solve the concerned radiative transfer problem. en_US
dc.language.iso en en_US
dc.publisher IOP Publishing en_US
dc.subject Line: formation en_US
dc.subject Methods: numerica en_US
dc.subject Polarization en_US
dc.subject Radiative transfer en_US
dc.subject Scattering en_US
dc.subject Sun: atmosphere en_US
dc.title Polarized line formation with lower-level polarization and partial frequency redistribution en_US
dc.type Article en_US


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