  The Coronal Global Evolutionary Model (CGEM) provides data-driven simulations
of the magnetic field in the solar corona to better understand the build-up of
magnetic energy that leads to eruptive events. The CGEM project has developed
six capabilities. CGEM modules (1) prepare time series of full-disk vector
magnetic field observations to (2) derive the changing electric field in the
solar photosphere over active-region scales. This local electric field is (3)
incorporated into a surface flux transport model that reconstructs a global
electric field that evolves magnetic flux in a consistent way. These electric
fields drive a (4) 3D spherical magneto-frictional (SMF) model, either at
high-resolution over a restricted range of solid angle or at lower resolution
over a global domain, to determine the magnetic field and current density in
the low corona. An SMF-generated initial field above an active region and the
evolving electric field at the photosphere are used to drive (5) detailed
magneto-hydrodynamic (MHD) simulations of active regions in the low corona. SMF
or MHD solutions are then used to compute emissivity proxies that can be
compared with coronal observations. Finally, a lower-resolution SMF magnetic
field is used to initialize (6) a global MHD model that is driven by an SMF
electric-field time series to simulate the outer corona and heliosphere,
ultimately connecting Sun to Earth. As a demonstration, this report features
results of CGEM applied to observations of the evolution of NOAA Active Region
11158 in February 2011.
