Scattering Polarization of the Spectral Lines in the Solar Chromosphere

Abstract:

Linear polarization produced by scattering of light and its magnetic field modification (namely, Hanle effect) in spectral lines can be used as diagnostic tools to understand the structuring of the solar atmosphere and the physical processes that produce and modify the linear, scattering poalrization signals. Modeling observations of strong spectral lines such as Ca II K at 3933 A using model solar atmosphers can give information on the less understood solar chromosphere, where this line is formed. Modeling the observations of the scattering poalrization in spectral lines requires the solution of polarized radiative transfer equation. Although solution is easier in one-dimenion, to be more realistic we must go for multi-dimensional geometries. In particular Ca II K line is appropriate for chromospheric diagnostics as it contains information on the less understood topics such as (1) scattering mechansim called partial frequency redistribution, (2) effect of magnetic field on line polarization in the chromosphere through Hanle effect, and (3) spatial structuring of the chromosphere that cause modifications in line polarization. Our aim here is to address these three topics through modeling the observations of Ca II K line using different model solar atmospheres.