Expanding Box simulations: implications the Solar Probe Plus and Solar Orbiter missions.

Recent three-dimensional simulations in the Expanding Box Model (EBM) show how the radial evolution of the spectral anisotropy of turbulence depends on the unknown coronal spectrum. However, regardless of the source spectrum, the solar wind expansion causes 1) the emergence of microstream structures and 2) a well defined component anisotropy.I will discuss the implications of such findings for the expected turbulent spectrum in the inner heliosphere and for the identification of microstreams in Solar Probe Plus records. I will also show how the EBM can be used to cross-check the 1D spectrum and to get insights on the unknown 3D structure of turbulence during radial alignment configurations of Solar Orbiter and Solar Probe Plus.