A reduction of total mean turbulent pressure due to the presence of magnetic
fields was previously shown to be a measurable effect in direct numerical
simulations. However, in the studied parameter regime the formation of
large-scale structures, as anticipated from earlier mean-field simulations, was
not found. An analysis of the relevant mean-field parameter dependency and the
parameter domain of interest is conducted in order to clarify this apparent
discrepancy.Comment: 3 pages, 2 figures, proceedings of IAU Symp. 274, Advances in Plasma
Astrophysics, ed. A. Bonanno, E. de Gouveia dal Pino and A. Kosoviche