Observing MHD turbulence in the solar wind

Solar wind MHD turbulence can be described as a mixture of inward and out- ward stochastic Alfv ́ nic fluctuations, including also convected structures, dominated by an e excess of magnetic energy. This study focuses on the role that magnetically dominated fluc- tuations have within the solar wind turbulence. This kind of fluctuations can be interpreted as non-propagating structures, advected by the wind during its expansion. In particular, observations performed in the ecliptic revealed a clear radial dependence of these mag- netic structures within fast wind, but not within slow wind. At short heliocentric distances (0.3AU), the turbulent population is largely dominated by Alfv ́ nic fluctuations charac- e terised by high values of normalised cross-helicity and a remarkable level of energy equipar- tition. However, as the wind expands, another population, characterised by lower values of Alfv ́ nicity and a clear imbalance in favour of magnetic energy becomes visible and clearly e distinguishable from the Alfv ́ nic population.