Tuesday

The bow shock is formed by the interaction between the supersonic solar wind and the semi-impermeable magnetopause. The position and shape has been a subject of several studies, many of which fit a two-dimensional surface to in situ shock crossings. These have shown to find a high dependence on the upstream solar wind parameters and the magnetopause shape. However, in-situ crossings are very sparse and biased toward events when the boundaries are in motion, and rarely give simultaneous information about the magnetopause and bow shock. Hence, it is impossible to view the whole bow shock and magnetopause at once.
Global simulations allow us to capture the entire magnetospheric system at an instant in time, and thus reveal the interconnection between different plasma regions and dynamics on large scales. The bow shock and magnetopause are calculated self consistently, allowing the boundaries to vary according to the solar wind input. In this work, we present global MHD simulations of the Earth’s magnetosphere using Gorgon, a 3D resistive MHD code. By applying real solar wind from ACE, we investigate the dynamic movement of the outer boundaries’ position and shape as they respond to the change in solar wind conditions. The results suggest that the spacecraft shock crossings may not fully represent the shock, as they only observe the shock while in motion.