Validating a Physics Based Space Weather Model

Abstract:

As part of our ongoing NSF PRE-EVENTS project, we have been working on developing and improving our physics based space weather models starting with coronal mass ejections (CMEs) originating from active regions of the Sun, propagation of CMEs through the heliosphere, their interaction with the magnetosphere and eventual impacts in the near space environment and on the ground. The main goal of our project is to provide reliable estimates for the impact of extreme space weather events. Since extreme events do not occur frequently and are not well observed, we need to rely on physics based models. As a first step, we are validating our models with under quiet or moderate conditions. We are comparing our Alfven Wave Solar atmosphere Model (AWSoM) predictions with line-of-sight extreme ultraviolet (EUV) images, coronal tomography and in situ solar wind and magnetic field measurement near the Earth under solar minimum conditions. We also study the behavior of our magnetohydrodynamic with embedded particle-in-cell (MHD-EPIC) model of the magnetosphere under steady solar wind driving conditions. We are studying both the dayside and magnetotail reconnection process. On the dayside we compare the model with observations of flux transfer events and kinetic scale observations by the MMS space craft. For the magnetotail we study the dynamics of the reconnection process that appears to reproduce several features of sawtooth events for strong but steady driving with negative Bz field. Overall, our physics based models perform reasonably well under quiet and steady conditions. This is a necessary condition to simulate dynamic and potentially extreme space weather events reliably.