NLTE Spectral Synthesis Based on 3D MHD Simulations – Towards the understanding of
the role of small scale magnetic field for the quiet Sun intensity
Margit Haberreiter [Margit.Haberreiter@lasp.colorado.edu] and Mark Rast, Laboratory for
Atmospheric and Space Physics (LASP), University of Colorado, Boulder; Sven WedemeyerBoehm, Institute of Theoretical Astrophysics, University of Oslo, Norway, and Center of
Mathematics for Applications, University of Oslo, Norway; Scott McIntosh, High Altitude
Observatory (HAO), National Center for Atmospheric Research (NCAR), Boulder, Colorado
The magnetic field is considered to be the main driver for total and spectral irradiance
variations. However, the detailed physics behind this phenomenon is not yet fully
understood. In this paper we analyze the effect of small-scale magnetic field on various
spectral lines and continuum wavelengths calculated with the NLTE radiative transfer code
Solar Modeling in 3D (SolMod3D). The code allows us to calculate NLTE level populations
and line spectra based on 3D MHD simulations carried out with CO5BOLD. This enables us
to study in great detail the effect of the varying small-scale magnetic field on the intensity
variations. These results are crucial for a better understanding of the role of small-scale
magnetic field in the irradiance variations.