Effect of Cross-redistribution on the Resonance Scattering Polarization of O I Line at 1302 Å

Abstract

Oxygen is the most abundant element on the Sun after hydrogen and helium. The intensity spectrum of resonance lines of neutral oxygen, namely, O I (1302, 1305, and 1306 Å), has been studied in the literature for chromospheric diagnostics. In this paper, we study the resonance scattering polarization in the O I line at 1302 Å using two-dimensional (2D) radiative transfer in a composite atmosphere constructed using a 2D magneto-hydrodynamical snapshot in the photosphere and columns of the one-dimensional FALC atmosphere in the chromosphere. The methods developed by us recently in a series of papers to solve multi-dimensional polarized radiative transfer have been incorporated in our new code POLY2D, which we use for our analysis. We find that multi-dimensional radiative transfer including XRD effects is important in reproducing the amplitude and shape of scattering polarization signals of the O I line at 1302 Å.