On the Sensitivity of Partial Redistribution Scattering Polarization Profiles to Various Atmospheric Parameters

TL;DR

This study investigates how various atmospheric parameters influence the scattering polarization profiles under partial frequency redistribution in solar atmosphere models, highlighting the sensitivity of polarization to thermal structure and damping variations.

Contribution

It provides a detailed analysis of the impact of atmospheric parameters on PRD scattering polarization profiles and introduces a frequency integrated anisotropy factor related to emergent polarization.

Findings

Complete frequency redistribution approximates weak resonance lines.

Linear polarization profiles are sensitive to thermal structure.

Damping parameter variations significantly affect polarization profiles.

Abstract

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 several atmospheric parameters on the emergent fractional linear polarization profiles. The shapes of these $Q/I$ profiles are interpreted in terms of the anisotropy of the radiation field, which in turn depends on the source function gradient that sets the angular variation of the specific intensity. We define a suitable frequency integrated anisotropy factor for PRD that can be directly related to the emergent linear polarization. We show that complete frequency redistribution is a good approximation to model weak resonance lines. We also show that the emergent linear polarization profiles can be very sensitive to the thermal structure of the solar atmosphere and, in particular, to spatial variations of the damping parameter.