MHD turbulence and the heating of astrophysical plasmas

Magnetohydrodynamic (MHD) turbulence plays a major role in the dynamics and thermodynamics of astrophysical plasmas in many environments and over a wide range of scales and parameters: primary examples are the heating of stellar and accretion disk coronae, acceleration of stellar winds, and star formation in molecular clouds. In the case of the solar wind and corona in situ measurements and remote-sensing observations have given the most detailed experimental knowledge of the interplay between large-scale driving forces, the development of a turbulent cascade, and the collisionless kinetics of dissipation, than in any other natural magnetized plasma environment (with the possible exception of the earth's magnetosphere). The questions of coronal and solar wind acceleration will be reviewed here within the general context of MHD turbulence and nonlinear interactions, from the large-scale energy sources and driving to the dissipation scales dominated by wave-particle interactions, from the special role of Alfven waves to the naturally intermittent nature of coronal energy release and solar flares.