Intermittency in space plasma turbulence

We present a short overview on theoretical aspects and observational findings about intermittency in solar wind MHD turbulence. This phenomenon, which became a remarkable topic in the past few years, is due to the fact that solar wind fluctuations are neither isotropic nor scale-invariant, two of the fundamental hypotheses at the basis of K41 Kolmogorov's theory. As a matter of fact, intermittency reflects in an inhomogeneous energy transfer during the turbulent cascade. In such conditions, time series alternate intervals of very high activity to intervals of quiescence. We will first introduce the problem of intermittency from a theoretical point of view, mentioning also different models apt to reproduce statistical features of turbulent intermittent behaviour. Afterwards, we will show how intermittency affects solar wind parameters, how intermittency evolves with heliocentric distance from the sun and how typical interplanetary events causing intermittency look like.