On July 22, 2004, the WIND spacecraft detected a typical interplanetary shock. There was sustaining weak southward magnetic field in the preshock region and the southward field was suddenly enhanced across the shock front (i.e., southward turning). When the shock impinged on the magnetosphere, the magnetospheric plasma convection was abruptly enhanced in the central plasma sheet, which was directly observed by both the TC-1 and Cluster spacecraft located in different regions. Simultaneously, the Cluster spacecraft observed that the dawn-to-dusk electric field was abruptly enhanced. The variations of the magnetic field observed by TC-1, Cluster, GOES-10 and GOES-12 that were distributed in different regions in the plasma sheet and at the geosynchronous orbit are obviously distinct. TC-1 observations showed that the magnetic intensity kept almost unchanged and the elevation angle decreased, but the Cluster spacecraft, which was also in the plasma sheet and was further from the equator, observed that the magnetic field was obviously enhanced. Simultaneously, GOES-12 located near the midnight observed that the magnetic intensity sharply increased and the elevation angle decreased, but GOES-10 located in the dawn side observed that the magnetic field was merely compressed with its three components all sharply increasing. Furthermore, the energetic proton and electron fluxes at nearly all channels observed by five LANL satellites located at different magnetic local times (MLTs) all showed impulsive enhancements due to the compression of the shock. The responses of the energetic particles were much evident on the dayside than those on the nightside. Especially the responses near the midnight were rather weak. In this paper, the possible reasonable physical explanation to above observations is also discussed. All the shock-induced responses are the joint effects of the solar wind dynamic pressure pulse and the magnetic field southward turning. solar wind dynamic pressure pulse, interplanetary shock, plasma sheet, geosynchronous orbit The magnetospheric energy is partly transferred from solar wind. On the other hand, the changes of solar wind plasma and interplanetary magnetic field (IMF) usually cause many kinds of disturbances in the magnetosphere and ionosphere. IMF B Z and solar wind dynamic pressure P dy are two important parameters that affect the solar wind-magnetosphere coupling [1] . In previous studies, the effects of IMF B Z to the magnetospheric activities have been received much attention, but the effects of solar wind dynamic pressure Pdy have not been clearly established. Often Pdy changes with the form of an abrupt enhancement in a few minutes, i.e., solar wind dynamic pressure pulses (DPPs) that are associated with interplanetary shocks or other discontinuities. When the solar wind dynamic pressure pulse interacts with the magnetosphere, it compresses the dayside magnetosphere earthward and causes eastward magnetopause
