POLARIZED LINE FORMATION IN MOVING ATMOSPHERES WITH PARTIAL FREQUENCY REDISTRIBUTION AND A WEAK MAGNETIC FIELD

Journal Article · Sat Oct 10 04:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/812/1/28· OSTI ID:22518851

Sampoorna, M.

The dynamical state of the solar and stellar atmospheres depends on the macroscopic velocity fields prevailing within them. The presence of such velocity fields in the line formation regions strongly affects the polarized radiation field emerging from these atmospheres. Thus it becomes necessary to solve the radiative transfer equation for polarized lines in moving atmospheres. Solutions based on the “observer’s frame method” are computationally expensive to obtain, especially when partial frequency redistribution (PRD) in line scattering and large-amplitude velocity fields are taken into account. In this paper we present an efficient alternative method of solution, namely, the comoving frame technique, to solve the polarized PRD line formation problems in the presence of velocity fields. We consider one-dimensional planar isothermal atmospheres with vertical velocity fields. We present a study of the effect of velocity fields on the emergent linear polarization profiles formed in optically thick moving atmospheres. We show that the comoving frame method is far superior when compared to the observer’s frame method in terms of the computational speed and memory requirements.

• OSTI ID: 22518851
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 812; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CHROMOSPHERE
COMPARATIVE EVALUATIONS
MAGNETIC FIELDS
POLARIZATION
RADIANT HEAT TRANSFER
SCATTERING
SUN
VELOCITY