Magnetospheric Science - Global Simulations: Capabilities and Limitations

The solar wind provides the source energy for many magnetospheric processes. These processes, like magnetic reconnection and particle acceleration, sculpt the global plasma structures that define the Earth's magnetosphere. Observations from different missions have been key to understanding these processes, but limitations on where and when the datasets are available make it challenging to understand the system as a whole. As a consequence, for many years global MHD and empirical models have been used to understand the solar wind-magnetosphere global interaction. However, many assumptions are made within these models that do not exactly describe the fundamental physical processes happening within the magnetosphere. This study aims to understand the different predictions given by the MHD models for the location of the magnetopause, the boundary that separates the solar wind from the Earth's magnetosphere. The predicted magnetopause position is then compared to results from empirical models, and to cases for extreme solar wind conditions where magnetopause crossings of the geosynchronous orbit have been observed. Rigorous analysis and comparison of observations and models for this boundary is critical in understanding magnetosphere dynamics for processes like magnetic reconnection. Understanding the differences and limitations of these models is imperative for improving and validating such models. These efforts will allow us to increase forecasting capabilities for space weather events and geomagnetic activity. Recently, the field has seen a host of novel magnetosphere imaging techniques that go hand-in-hand with the development and improvement of these global models that encapsulate the fundamental physical processes and predict their diagnostic signatures. A global magnetosphere imager, for example, would significantly help in understanding many of the main magnetospheric processes and would be critical for current and future model validation.