Magnetic field data acquired at high-latitude, near-conjugate stations (Iqaluit, Northwest Territories, Canada, and South Pole Station, Antarctica) are studied in order to examine in more detail the nature of magnetic ''impulse'' signatures that occur in the data and that are produced by ionosphere currents which are caused by magnetopause processes. An examination of the data, both visually and with a computer algorithm ''detector,'' from the 5-month interval July--November 1985 found many such magnetic ''impulse'' events which could be interpreted in terms of intense field-aligned currents above the observing stations. All the events have a half-width in time of a few minutes, and most are reasonable conjugate. The majority of the events studied have magnetic field perturbations in the vertical component which can be interpreted in terms of field-aligned currents directed in the same direction (either into or out of the ionosphere) in both hemispheres. The perturbations in the horizontal plane are consistent with an interpretation in terms of a single cycle of an odd mode Alfv¿n wave. For the events shown in detail in this paper, the impulsive magnetic signatures are found to occur for the interplanetary magnetic field BZ component positive, negative, or variable. The observations are discussed in the context of some contemporary ideas on the generation of ionospheric disturbances by magnetopause processes such as sporadic reconnection (''flux transfer events''), plasma injections into the low-latitude boundary layer, Kelvin--Helmholtz instability, and solar wind ''pressure pulses.'' Near-equatorial data from a location in the same local time section as the high-latitude data are used to show the gross differences in global ionospheric currents stimulated by sudden commencements and by the magnetic impulse events. ¿ American Geophysical Union 1990