Waves and turbulence in the cusp, at the magnetopause and its vicinity as seen by the Cluster STAFF experiment : characterisation and role on particle dynamics.

Abstract

Key regions of the interface between the Solar Wind and the Earth's magnetosphere, as the cusp and the magnetopause are known to be populated by plasma waves and turbulence. The role of the strong ULF waves at the magnetopause, recognised as being "turbulent like" and very intense is questioned on its possibility to transfer particle mass, energy and momentum from the Solar Wind into the magnetosphere, for instance via the so-called Flux Transfer Events. The Cluster spacecraft, thanks to the tetrahedron position of the 4 spacecraft, specially with small separations, allow to use special tools, as the k-filtering method to identify "linear" modes in turbulent-like structures, the curl B method to calculate currents e.g. in FTEs (to which turbulent like ULF waves are associated). These new results can now be compared with theoretical predictions. A special emphasis will be put on the cusp region, seat of a different kind of waves. In particular the same k-filtering tool will be applied to determine the modes of the turbulent like waves, and whose role in diffusing injected ions will be evidenced