A study of Pc 3-4 pulsations observed by the Cluster satellites and multiple ground-based observatories

Although the dominant source of Pc 3 magnetic pulsations in Earth's magnetosphere is now understood to be in the ion foreshock region upstream of Earth's bow shock, the paths by which these waves travel toward Earth are still not well understood. In this study we present observations of several Pc 3 events observed in late 2001 both by the Cluster satellites and by arrays of ground observatories. During the majority of the events studied Cluster observed Pc 3 activity while passing latitudinally through the dayside outer magnetosphere, but in two cases Cluster observed waves at high altitudes deep in the polar cap. IMF data were used to confirm that conditions were favorable for the generation of upstream waves during most of these events: the IMF was nearly radial (low cone angle), and the IMF magnitude was consistent with the frequency of the waves observed both at the satellites and on the ground, based on the empirical relation f (in mHz) ~ 6 |B| (in nT). Signals at the four Cluster satellites and at various ground stations will be compared in order to test competing transport models, including direct subsolar propagation via fast mode waves and indirect high latitude propagation via the cusp/cleft regions.