MHD simulation of a fast forward shock event

Following the propagation of interplanetary shocks (IPS) in the solar wind and throughout the Earth's magnetosphere is vital to understand the processes associated with their interaction with the magnetosphere. A case study using multiple spacecraft analysis and GUMICS-4 global MHD simulation shows that stronger fast forward shocks with a higher shock speed cause a greater response in the magnetosphere. Additionally, a statistical analysis of a set of fast forward shock events shows that the solar wind speed and dynamic pressure play an important role in the geomagnetic activity: Our results show that higher interplanetary shock speeds cause a higher response in the AE index. Furthermore, we have used the GUMICS-4 global MHD simulation results to interpret the unusual double step structure observed at geostationary orbit. The temporal variations in the velocity and electric field in the dayside magnetosphere near geostationary orbit strongly suggest that the second part of the double step structure is a reflected disturbance from the inner boundary of the magnetosphere.