Spectral line polarization with angle-dependent partial frequency redistribution. I. A Stokes parameters decomposition for Rayleigh scattering

Details Spectral line polarization with angle-dependent partial frequency redistribution. I. A Stokes parameters decomposition for Rayleigh scattering Spectral line polarization with angle-dependent partial frequency redistribution. I. A Stokes parameters decomposition for Rayleigh scattering

Nov 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010a%26a...522a..41f&link_type=abstract

Astronomy and Astrophysics, Volume 522, id.A41

Astronomy and Astrophysics

Astrophysics

4

Line: Formation, Polarization, Radiative Transfer

Scientific paper

Context. The linear polarization of a strong resonance lines observed near the solar limb is created by a multiple-scattering process. Partial frequency redistribution (PRD) effects must be accounted for to explain the polarization profiles. The redistribution matrix describing the scattering process is a sum of terms, each containing a PRD function multiplied by a Rayleigh type phase matrix. A standard approximation made in calculating the polarization is to average the PRD functions over all the scattering angles, because the numerical work needed to take the angle-dependence of the PRD functions into account is large and not always needed for reasonable evaluations of the polarization. Aims: This paper describes a Stokes parameters decomposition method, that is applicable in plane-parallel cylindrically symmetrical media, which aims at simplifying the numerical work needed to overcome the angle-average approximation. Methods: The decomposition method relies on an azimuthal Fourier expansion of the PRD functions associated to a decomposition of the phase matrices in terms of the Landi Degl'Innocenti irreducible spherical tensors for polarimetry T^K_Q(i, Ω) (i Stokes parameter index, Ω ray direction). The terms that depend on the azimuth of the scattering angle are retained in the phase matrices. Results: It is shown that the Stokes parameters I and Q, which have the same cylindrical symmetry as the medium, can be expressed in terms of four cylindrically symmetrical components I_Q^K (K = Q = 0, K = 2, Q = 0, 1, 2). The components with Q = 1, 2 are created by the angular dependence of the PRD functions. They go to zero at disk center, ensuring that Stokes Q also goes to zero. Each component I_Q^K is a solution to a standard radiative transfer equation. The source term S_Q^K are significantly simpler than the source terms corresponding to I and Q. They satisfy a set of integral equations that can be solved by an accelerated lambda iteration (ALI) method.

Affiliated with

Also associated with

No associations

Rating

Spectral line polarization with angle-dependent partial frequency redistribution. I. A Stokes parameters decomposition for Rayleigh scattering does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Spectral line polarization with angle-dependent partial frequency redistribution. I. A Stokes parameters decomposition for Rayleigh scattering, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectral line polarization with angle-dependent partial frequency redistribution. I. A Stokes parameters decomposition for Rayleigh scattering will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1156486