Solar wind turbulence: intermittent structures and the role of ion thermal pressure

The nature of the magnetic field fluctuations in the solar wind at kinetic scales is still under debate. Here we study coherent structures responsible for solar wind intermittency around ion characteristic scales. We find that in the fast solar wind intermittency is due to current sheets and Alfven vortex like structures. In the slow solar wind, we observe as well compressible structures like magnetic solitons, holes and shocks. Using multi-satellite analysis of Cluster measurements, we can estimate propagation speed in the plasma rest frame and the topology of the observed coherent structure. We show that all structures, in fast and slow wind, have k_perp >> k_|| wavevector anisotropy and that some of them propagate in the plasma rest frame. We discuss possible interpretation of the observed structures and their role in heating of plasma. We show as well a strong correlation between the turbulence level and the ion thermal pressure valid between 0.3 and 5.4 AU and we discuss its possible origine, like turbulence heating or fossile feature in the solar wind.