Ring current formation in the coupled GAMERA-RCM model

Abstract:

There have been numerous efforts to develop a comprehensive and self-consistent model of the global magnetosphere. The models are typically built on top of a global MHD model into which other physics-based models are integrated. In this presentation, we describe a recently developed coupled model that combines the GAMERA global MHD code with the Rice Convection Model (RCM). This model was developed as part of the NASA Drive Center for Geospace Storms (CGS), includes a number of model improvements that seeks to avoid some of the challenges earlier models have encountered. One such improvement is a new procedure that adjusts the pressure and density that is returned by the RCM to GAMERA code by approximately taking into account the change in the magnetic field while still maintaining total entropy conservation. Another important consideration is the effects of bursty bulk flows (BBFs). It is now believed that the majority of the transport from the plasma sheet to the inner magnetosphere is via BBFs, which violates the RCM’s assumption of slow flow. We will describe how this addressed in the coupled model, as well as briefly mention other model modifications such as a dynamic plasmasphere, an initial quiet time ring current, and electron precipitation and discuss the impacts of these model changes on the formation and evolution of the ring current.