• firehose
• intermittency
• magnetosphere
• mirror
• numerical simulations
• solar wind
• structure functions
• temperature anisotropy
• turbulence

In this thesis, I have analyzed the statistical turbulent properties of the solar wind used in the innovative numerical simulation Menura. Specifically, I firstly examine the magnetic field data resulting from a 3D simulation of solar wind decaying turbulence. The analysis of the magnetic field fluctuations has been performed by investigating the corresponding structure functions (SF). They allow to show if the hypothesis of isotropic turbulence is actually valid, in other words if the resulting fluctuating plasma can be really called a turbulent plasma. Furthermore, SF are fundamental mathematical instruments to distinguish between self-similar and intermittent turbulent systems, in other words if the magnetic fluctuations homogeneously fill the space independently of the physical scale or tend to concentrate in some regions without filling the whole space. The final stage of the simulation represents the starting point for a second run modeling the interaction of the turbulent solar wind with the magnetosphere of a compact object. Moreover, in such a context, plasma micro-instabilities, like the fire-hose and mirror instability, could come into play due to high temperature anisotropy that are expected to form in the magnetosheath, i.e. the layer of shocked solar wind just before the magnetopause. In the second part of the thesis, I have investigated the possible presence of temperature anisotropy (with respect to the mean magnetic field direction) and determined if the conditions for the fire-hose and mirror instability are actually satisfied. Moreover, I have analyzed if the simulation resolution is sufficient to allow the instabilities to develop correctly and so to redistribute the amount of free energy carried by anisotropy.