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$F$-state interference significantly modifies the polarization produced by scattering processes in the solar atmosphere. Its signature in the emergent Stokes spectrum in the absence of magnetic fields is depolarization in the line core. In…

Solar and Stellar Astrophysics · Physics 2015-12-25 K. Sowmya , K. N. Nagendra , J. O. Stenflo , M. Sampoorna

The long-standing paradox of the linear polarization signal of the Na i D1 line was recently resolved by accounting for the atom's hyperfine structure and the detailed spectral structure of the incident radiation field. That modeling relied…

Solar and Stellar Astrophysics · Physics 2023-09-25 Gioele Janett , Ernest Alsina Ballester , Luca Belluzzi , Tanausú del Pino Alemán , Javier Trujillo Bueno

The quantum interference between the fine structure states of an atom modifies the shapes of the emergent Stokes profiles in the Second Solar Spectrum. This phenomenon has been studied in great detail both in the presence and absence of…

Solar and Stellar Astrophysics · Physics 2015-06-22 K. Sowmya , K. N. Nagendra , M. Sampoorna , J. O. Stenflo

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…

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

Context. The correct modeling of the scattering polarization signals observed in several strong resonance lines requires taking partial frequency redistribution (PRD) phenomena into account. Aims. This work aims at assessing the impact and…

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

This paper presents a detailed study of the scattering polarization profiles formed under partial frequency redistribution (PRD) in two thermal models of the solar atmosphere. Particular attention is given to understanding the influence of…

Solar and Stellar Astrophysics · Physics 2010-10-12 M. Sampoorna , J. Trujillo Bueno , E. Landi Degl'Innocenti

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

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

The Ba II D2 line at 4554 A is a good example, where the F-state interference effects due to the odd isotopes produce polarization profiles, which are very different from those of the even isotopes that do not exhibit F-state interference.…

Solar and Stellar Astrophysics · Physics 2014-09-02 H. N. Smitha , K. N. Nagendra , J. O. Stenflo , M. Sampoorna

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

Quantum interference phenomena manifests itself in several ways in the polarized solar spectrum formed due to coherent scattering processes. One such effect arises due to interference between the fine structure (J) states giving rise to…

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

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…

Partial frequency redistribution (PRD), describing the formation of the line profile, has negligible observational effects for optical depths smaller than ~10^3, at the resolving power of most current instruments. However, when the spectral…

Earth and Planetary Astrophysics · Physics 2015-05-27 Roxana E. Lupu , Paul D. Feldman , Stephan R. McCandliss , Darrell F. Strobel

Recent theoretical investigations have pointed out that the cores of the Ly-alpha lines of H I and He II should show measurable scattering polarization signals when observing the solar disk, and that the magnetic sensitivity, through the…

Solar and Stellar Astrophysics · Physics 2015-06-05 Luca Belluzzi , Javier Trujillo Bueno , Jiri Stepan

Interference between magnetic substates of the hyperfine structure states belonging to different fine structure states of the same term influences the polarization for some of the diagnostically important lines of the Sun's spectrum, like…

Solar and Stellar Astrophysics · Physics 2015-12-25 K. Sowmya , K. N. Nagendra , M. Sampoorna , J. O. Stenflo

Quantum interference effects play a vital role in shaping the linear polarization profiles of solar spectral lines. The Ba II D2 line at 4554 A is a prominent example, where the F-state interference effects due to the odd isotopes produce…

Solar and Stellar Astrophysics · Physics 2015-06-15 H. N. Smitha , K. N. Nagendra , J. O. Stenflo , M. Sampoorna

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…

Radiative transfer modeling of spectral lines including partial redistribution (PRD) effects requires the evaluation of the ratio of the emission to the absorption profile. This quantity requires a large amount of computational work if one…

Solar and Stellar Astrophysics · Physics 2015-06-05 Jorrit Leenaarts , Tiago Pereira , Han Uitenbroek

Hanle scattering is an important diagnostic tool to study weak solar magnetic fields. Partial frequency redistribution (PRD) is necessary to interpret the linear polarization observed in strong resonance lines. Usually angle-averaged PRD…

Solar and Stellar Astrophysics · Physics 2013-04-22 H. D. Supriya , M. Sampoorna , K. N. Nagendra , B. Ravindra , L. S. Anusha
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