TOWARD A REALISTIC THERMODYNAMIC MAGNETOHYDRODYNAMIC MODEL OF THE GLOBAL SOLAR CORONA
In this work, we describe our implementation of a thermodynamic energy equation into the global corona model of the Space Weather Modeling Framework and its development into the new lower corona (LC) model. This work includes the integration of the additional energy transport terms of coronal heating, electron heat conduction, and optically thin radiative cooling into the governing magnetohydrodynamic (MHD) energy equation. We examine two different boundary conditions using this model; one set in the upper transition region (the radiative energy balance model), as well as a uniform chromospheric condition where the transition region can be modeled in its entirety. Via observation synthesis from model results and the subsequent comparison to full Sun extreme ultraviolet and soft X-ray observations of Carrington rotation 1913 centered on 1996 August 27, we demonstrate the need for these additional considerations when using global MHD models to describe the unique conditions in the low corona. Through multiple simulations, we examine the ability of the LC model to assess and discriminate between coronal heating models, and find that a relative simple empirical heating model is adequate in reproducing structures observed in the low corona. We show that the interplay between coronal heating and electron heat conduction provides significant feedback onto the three-dimensional magnetic topology in the low corona as compared to a potential field extrapolation, and that this feedback is largely dependent on the amount of mechanical energy introduced into the corona.
The Astrophysical Journal
Digital Object Identifier (DOI)
Cooper Downs, Ilia I. Roussev, Bart van der Holst, Noé Lugaz, Igor V. Sokolov, and Tamas I. Gombosi. TOWARD A REALISTIC THERMODYNAMIC MAGNETOHYDRODYNAMIC MODEL OF THE GLOBAL SOLAR CORONA. Astrophysical Journal. 712:1219-1231. 2010