Coronal Mass Ejections in a Data-Driven Global Magnetohydrodynamic Model

The solar wind (SW) emerging from the Sun is the main driving mechanism of solar events which may lead to geomagnetic storms that are the primary causes of space weather disturbances that affect the magnetic environment of... [ view full abstract ]

The solar wind (SW) emerging from the Sun is the main driving mechanism of solar events which may lead to geomagnetic storms that are the primary causes of space weather disturbances that affect the magnetic environment of Earth and may have hazardous effects on the space-borne and ground-based technological systems as well as human health. For this reason, accurate modeling of the background SW is a necessary part of space weather forecasting. Geomagnetic storms are caused both by SW stream interactions and by the largest solar coronal disturbances called coronal mass ejections (CMEs). Therefore, understanding the fundamental physical processes underlying CME generation mechanisms is a key area of research in solar physics and another essential part of space weather forecasting. 

We have developed a data driven magnetohydrodynamic (MHD) model of the global solar corona. Such models have become more and more popular as the quantity and quality of available observational data increased significantly over the past two decades. We apply characteristic boundary conditions (BCs) at our inner boundary located at lower corona. The use of characteristic BCs is necessary to apply observational data into the model equations in a both physically and mathematically-consistent way. Our global solar corona model can be driven by different observational data including Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) synoptic vector magnetograms together with the horizontal velocity data in the photosphere obtained by either the time-distance helioseismology method or the Differential Affine Velocity Estimator for Vector Magnetograms (DAVE4VM) method, and the line-of-sight (LOS) magnetogram data obtained by HMI, Solar and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI), National Solar Observatory/Global Oscillation Network Group (NSO/GONG) and Wilcox Solar Observatory (WSO). The CME generation mechanism that we apply is based on introducing Gibson-Low flux rope model to our data-driven background SW model. We determine the flux rope model parameters from observational data obtained by solar observation instruments onboard SDO, in particular HMI magnetograms and Atmospheric Imaging Assembly (AIA) solar corona images. 

We developed our data-driven model in the Multi-Scale Fluid-Kinetic Simulation Suite (MS-FLUKSS) which is arguably one of the most sophisticated numerical codes designed primarily for modeling the partially ionized plasma throughout and beyond the heliosphere using adaptive mesh refinement (AMR) technique on Cartesian or spherical grids. It scales well on major supercomputers such as XSEDE Stampede and NCSA Blue Waters. Thus, MS-FLUKSS is the ideal platform to further develop our data-driven model as an operational space weather prediction model, which is one of our major goals in the future.

We will present an overview of our data-driven MHD model together with the CME generation mechanism within MS-FLUKSS and show simulation results involving CMEs.