Back to Volume
Paper: A Quantitative Comparison of Observed and Theoretical Stokes Profiles of the Ca II 8542 Å Line in the Quiet Sun
Volume: 526, Solar Polarization Workshop 8
Page: 235
Authors: Jurčák, J.; Stěpán, J.; Bianda, M.; Trujillo Bueno, J.
Abstract: We present an analysis of the Stokes profiles of the Ca II 8542 Å line produced by the joint action of atomic level polarization and the Hanle and Zeeman effects. We compare spectropolarimetric observations of this line in a quiet region at the solar disk centre, taken with the ZIMPOL instrument at IRSOL, with the theoretical Stokes profiles computed with the PORTA radiative transfer code using as solar model atmosphere a 3D snapshot taken from a radiation MHD simulation of an enhanced-network region. Even though the spatial sampling of the ZIMPOL observations is only 1.43 arcsec/pixel, we detect Q/I, U/I and V/I polarization signals of the order of 0.1%. The synthetic line profiles have been obtained by solving the full 3D NLTE radiative transfer problem taking into account the symmetry breaking effects due to the model's horizontal inhomogeneities and macroscopic velocity gradients. After spatial and spectral degradation, in some locations we find similar amplitudes between the observed and calculated linear polarization profiles. However, in general, the observations show stronger polarization signals than the calculated ones, a discrepancy that could be used to refine the numerical models of the quiet solar chromosphere.
Back to Volume