Observations from various magnetometer networks, including Magnetomer Array for Cusp and Cleft Studies (MACCS), Canadian Auroral Network for the OPEN Program Unified Study (CANOPUS), the Greenland Coastal Chain, and the U.S./Russia Antarctic Array, made on January 5, 1995, show an event of very long period pulsations (30- to 40-min period) in the cusp region. Pulsations were driven by quasiperiodic Interplanetary Magnetic Field (IMF) By variations which were observed by the Wind spacecraft. Disturbances of this type are commonly interpreted as poleward moving, east-west oriented ionospheric currents (e.g., intensification of the DPY current system), stimulated by reconnection processes at the dayside magnetopause. However, the temporal/spatial, ground-based structure of such disturbances can better be described if this picture is augmented by the inclusion of transient wave processes, for example, distortions of the Alfven phase front, transmitting a disturbance from an assumed reconnection region to the ionosphere. In general, this type of disturbance, which we suggest calling PDPY6 pulsations, is shown to be a manifestation of the modulation of the high-latitude ionosphere electrodynamics by a large-scale Alfven wave in the solar wind under favorable IMF orientation. ¿ 2000 American Geophysical Union