ABSTRACT
The outer envelope of our nearest star, the sun, is a very complicated fluid dynamics laboratory. Observations reveal highly turbulent flows and fields, and yet a remarkable degree of large-scale coherence emerges from this chaos. High-performance computing is allowing simulations of the compressible gas dynamics to enter the turbulent regime at last, and the results are yielding transport properties which are at considerable variance with earlier laminar models. Such turbulent modelling is providing insight into the generation of the largest scales from small-scale disorder and thus also into the processes underlying the observed solar phenomena.
