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The spectral line polarization encodes a wealth of information about the thermal and magnetic properties of the solar atmosphere. Modeling the Stokes profiles of strong resonance lines is, however, a complex problem both from the…

Solar and Stellar Astrophysics · Physics 2017-02-22 Ernest Alsina Ballester , Luca Belluzzi , Javier Trujillo Bueno

Aims. The main goal of this paper is to present an accurate and efficient numerical strategy for solving the radiative transfer problem for polarised radiation in strong resonance lines forming out of local thermodynamic equilibrium, taking…

Our previous paper outlined the general aspects of the theory of radio light curve and polarization formation for pulsars. We predicted the one-to-one correspondence between the tilt of the linear polarization position angle of the and the…

High Energy Astrophysical Phenomena · Physics 2017-06-21 Hayk Hakobyan , Vasily Beskin , Alexander Philippov

We investigate the main physical mechanisms that shape the intensity and polarization of the Ba II D1 line at 4934 angstroms via radiative transfer numerical experiments. We focus especially on the scattering linear polarization arising…

Solar and Stellar Astrophysics · Physics 2024-01-24 E. Alsina Ballester , T. del Pino Alemán , J. Trujillo Bueno

An expression for the partial frequency redistribution (PRD) matrix for line scattering in a two-term atom, which includes the J-state interference between its fine structure line components is derived. The influence of collisions (both…

Solar and Stellar Astrophysics · Physics 2015-06-11 H. N. Smitha , K. N. Nagendra , M. Sampoorna , J. O. Stenflo

This paper presents a numerical application of a self-consistent theory of partial redistribution in non-LTE conditions, developed in previous papers of the series. The code was described in a previous paper of this series. However, in that…

Solar and Stellar Astrophysics · Physics 2021-01-04 V. Bommier

The importance of Partial Redistribution (PRD) in the modelling of the Lyman Alpha and Lyman Beta emission lines of hydrogen in stellar atmospheres is examined using simple atmospheric models of a range of late-type stars. These models…

Astrophysics · Physics 2009-11-06 Stuart A. Sim

We present the theoretical framework and numerical methods we have implemented to solve the problem of the generation and transfer of polarized radiation in spectral lines out of local thermodynamical equilibrium, while accounting for…

Solar and Stellar Astrophysics · Physics 2022-09-01 Ernest Alsina Ballester , Luca Belluzzi , Javier Trujillo Bueno

This work aims to identify the relevant physical processes in shaping the intensity and polarization patterns of the solar K I D lines through spectral syntheses, placing particular emphasis on the D2 line. The theoretical Stokes profiles…

Solar and Stellar Astrophysics · Physics 2022-08-26 Ernest Alsina Ballester

Radiative transfer (RT) studies of the linearly polarized spectrum of the Sun (the second solar spectrum) have generally focused on the line formation, with an aim to understand the vertical structure of the solar atmosphere using…

Solar and Stellar Astrophysics · Physics 2013-08-16 L. S. Anusha , K. N. Nagendra

To explain the linear polarization observed in spatially resolved structures in the solar atmosphere, the solution of polarized radiative transfer (RT) equation in multi-dimensional (multi-D) geometries is essential. For strong resonance…

Solar and Stellar Astrophysics · Physics 2013-08-16 L. S. Anusha , K. N. Nagendra

The linearly-polarized solar limb spectrum that is produced by scattering processes contains a wealth of information on the physical conditions and magnetic fields of the solar outer atmosphere, but the modeling of many of its strongest…

Solar and Stellar Astrophysics · Physics 2015-05-18 M. Sampoorna , J. Trujillo Bueno

The relation between the jump length probability distribution function and the spectral line profile in resonance atomic radiation trapping is considered for Partial Frequency Redistribution (PFR) between absorbed and reemitted radiation.…

Aims: The polarization of the Ca II resonant doublet (H and K lines) and the subordinate infrared triplet lines are key observables for diagnosing solar chromospheric magnetism. It is thus necessary to understand the physical mechanisms…

Solar and Stellar Astrophysics · Physics 2026-01-14 I. Juanikorena Berasategi , E. Alsina Ballester , T. del Pino Alemán , J. Trujillo Bueno

NASA's Interface Region Imaging Spectrograph (IRIS) space mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h&k lines as well as a slit-jaw imager centered at Mg II k.…

Solar and Stellar Astrophysics · Physics 2015-06-16 J. Leenaarts , T. M. D. Pereira , M. Carlsson , H. Uitenbroek , B. de Pontieu

Oxygen is the most abundant element on the Sun after Hydrogen and Helium. The intensity spectrum of resonance lines of neutral Oxygen namely O {\sc i} (1302, 1305 and 1306 \AA\,) has been studied in the literature for chromospheric…

Solar and Stellar Astrophysics · Physics 2015-06-22 L. S. Anusha , K. N. Nagendra , H. Uitenbroek

We study the effects of Rayleigh and Raman scattering on the formation of polarized spectral lines in a $\Lambda$-type multi-term atom. We fully take into account the partial redistribution of frequency and the presence of atomic…

Solar and Stellar Astrophysics · Physics 2016-06-29 R. Casini , R. Manso Sainz

Measurable linear scattering polarization signals have been predicted and detected at the solar disk center in the core of chromospheric lines. These forward-scattering polarization signals, which are of high interest for magnetic field…

Ca {\sc i} 4227 \AA\, line is a strong resonance line formed in the Solar chromosphere. At the limb, it produces the largest scattering polarization signal. So far, modeling the linear polarization in this line has been limited to the use…

Solar and Stellar Astrophysics · Physics 2025-03-11 Harsh Mathur , L. S. Anusha , Devang Agnihotri

Quantum interference effects together with partial frequency redistribution (PFR) in line scattering produce subtle signatures in the so called Second Solar Spectrum (the linearly polarized spectrum of the Sun). These signatures are…

Solar and Stellar Astrophysics · Physics 2019-10-25 M. Sampoorna , K. N. Nagendra , K. Sowmya , J. O. Stenflo , L. S. Anusha