Geosynchronous magnetic field responses to fast solar wind dynamic pressure enhancements: MHD field model

Abstract. We performed global MHD simulations of the geosynchronous magnetic field in response to fast solar wind dynamic pressure (P_d) enhancements. Taking three P_d enhancement events in 2000 as examples, we found that the main features of the total field B and the dominant component B_z can be efficiently predicted by the MHD model. The predicted B and B_z varies with local time, with the highest level near noon and a slightly lower level around mid-night. However, it is more challenging to accurately predict the responses of the smaller component at the geosynchronous orbit (i.e., B_x and B_y). In contrast, the limitations of T01 model in predicting responses to fast P_d enhancements are presented.