Ground observations of kinetic Alfven waves

Ground-based observations with the EISCAT magnetometer of locally confined intense drifting current systems and Geos-2 measurements during four events in November and December 1982 are examined. In the ground-based measurements near the Harang discontinuity, the events are characterized by strong pulsations with amplitudes in the horizontal component up to 1000 nT and periods of about 300 s and longer. They occur in the evening hours adjacent to the poleward side of the discontinuity with the onset of a substorm; at the same time, the inner edge of the plasma sheet passes the Geos-2 position, magnetically conjugate to ground stations. It is shown that the events can be explained in terms of kinetic Alfven waves. 8 references