Geosynchronous Magnetopause Crossings in February–April 2023

Abstract

Geosynchronous magnetopause crossings (GMCs) were analyzed during geomagnetic storms on February 26, March 23, and April 23, 2023. GMC-associated magnetosheath intervals were identified using magnetic data acquired from the GOES-16 and GOES-17 spacecraft. A comparative analysis of various magnetopause models was performed on the base of solar wind conditions measured by the THEMIS-E spacecraft and the Wind interplanetary monitor. The analysis of models was based on statistical parameters for determining magnetosheath intervals. It was shown that for all three storms, the model presented in [1] demonstrated the best accuracy. For events of moderate magnetic storms against the background of small negative Bz component of the interplanetary magnetic field (IMF), good results are obtained with the model described in [2]. For extreme events with very high solar wind pressures and/or very strong negative IMF Bz, the model shown in [3] exhibits good accuracy, and satisfactory accuracy is also demonstrated by models presented in [4, 5]. It was shown that the accuracy of the models was affected by the following factors and effects: the choice of interplanetary monitor, the dependence of the model on the solar wind pressure, the Bz saturation effect, the dawn–dusk magnetopause asymmetry, and the effect of prehistory.