Intermittency and extended self-similarity in the Solar Wind turbulence

We investigate the occurrence of Extended Self-Similarity and spatial intermittency in the Solar Wind Magnetohydrodynamic turbulence by using the Helios 2 bulk velocity data. We show that the velocity structure functions are not independent from each other, rather linear relations exist between the logarithms of structure functions of different order. The calculation of the slopes of these linear relations (scaling exponents) show that the slopes are the same whatever the heliocentric distance. By comparing these scaling exponents with that obtained in some ordinary turbulent flows, we show that a difference exists only for values of the order q higher than 10. This result allows us to conjecture that turbulence in ordinary fluid flows and MHD turbulence might display different intermittent behaviors at the smallest scales.