摘要：The aim of the present article was to analyze features of interactions between an interplanetary shock wave and the magnetosphere on the basis of comparative analysis of geomagnetic variations observed during a sudden commencement (SC) by satellites and ground-based stations with high time resolution. A case study of the interaction of an interplanetary shock wave (ISW) with the magnetosphere was carried out on April 23, 2012. Statistical analysis was based on 11 SC events occurring from 1988 to 2012. A precursor of SC in the form of a broadband electrо-magnetic pulse is detected globally in the frequency range of 0.2 to 6.5 Hz. The spectrum of pulses has a resonant structure. It is assumed that the structure results from a filtering effect of the ionosphere on MHD waves generated at the front of the ISW or in its interaction with the magnetopause.
