Abstract
Turbulence is a widespread phenomenon ranging from our daily experience of milk motion in a coffee cup to the formation of stars and galaxies, exhibiting random motion of fluid under a high Reynolds number. In astrophysical environments turbulence plays a crucial role to transport energy and angular momentum in order to maintain the system. Such examples can be found in dynamo, accretion disks, and cosmic rays. Astrophysical turbulence is also unique in that the medium is collision-free and furthermore it is electrically conducting, such that the fluid motion is
closely coupled to the electromagnetic interactions.
With the advent of the Cluster mission, the multi-spacecraft mission, it has finally become possible to study turbulence properties directly in the spatial domain. In the talk we review astrophysical turbulence in general and interpret the Cluster observations.
