Validation of Two MHD Models of the Solar Corona with Rotational Tomography

Abstract

We demonstrate a validation of two 3D MHD models of the corona by comparing density values from solar rotational tomography (SRT) to densities and morphological properties of the two MHD solutions for CR 2029 (2005 April 21-May 18). The two MHD models are given by the Stanford and Michigan models, and both use the same synoptic magnetogram from MDI as a lower boundary condition. The SRT reconstructions are based on polarized white-light images MLSO Mk IV data for the region between 1.1 and 1.5 R☉ (solar radii) and LASCO C2 for the region between 2.3 and 6.0 R☉. While the Stanford MHD model reasonably reproduces the tomographic density over the south pole, it fares less well over the north pole, and the Michigan MHD model underestimates the density over both poles. At lower latitudes, we find that while the MHD models have better agreement with the tomographic densities in the region below 3.5 R☉, at larger heights the agreement is more problematic. Our interpretation is that the base densities and temperatures of the models need to be improved, as well as their radial density gradients.