Ground observations of geomagnetic pulsations during a quiet magnetospheric interval correlated with satellite plasma measurements
Analytical results for five different geomagnetic pulsation events which occurred between 0 and 10 UT on November 28, 1977 are presented. The periods and latitudinal characteristics of the pulsations recorded on three chains of magnetometers in northern Europe are compared with theoretical eigenperiods calculated from simultaneous plasma density and composition measurements made in the plasmatrough and at the plasmapause by the relaxation sounder experiment and the Ion Composition Experiment on GEOS-1. The plasmapause was detected twice, by both measurement and experiment. Plasma density measurements were used to calculate the variation of the natural eigenperiods of different wave modes with latitude in the plasmatrough and at the plasmapause. The characteristics of the continuous pulsations generally corroborate the calculated eigenperiods. The Pi2 event provides evidence of a surface wave on the plasmapause with a period in close agreement with the calculated eigenperiod.