ON WAVE RELATED DENSITY STRUCTURES

Y.Khotyaintsev, K. Stasiewicz, A. Eriksson and M. André

Swedish Institute of Space Physics, Uppsala Division

Previous satellite measurements by Freja, Astrid II and Polar indicated relation of

density structures with Alfvénic and other wave activity. Coupling is possible due to

several mechanisms, e.g. ponderomotive effects, plasma heating, trapping of the

wave by large-scale density cavity and various instabilities occuring on density

gradient. We present multipoint observations from EFW instrument on Cluster II of

density structures and related wave activity in the magnetosphere and discuss

spatial-temporal nature of the phenomena.