Transition to Equilibrium and Coherent Structure in Ideal MHD Turbulence

Transition of ideal, homogeneous, incompressible, magnetohydrodynamic (MHD) turbulence to near-equilibrium from non-equilibrium initial conditions is examined through new long-time numerical simulations on a 1283 periodic grid. Here, we neglect dissipation because are primarily concerned with behavior at the largest scale which has been shown be essentially same for ideal and real (forced dissipative) MHD turbulence. A Fourier spectral transform method used numerically integrate dynamical equations forward in time results six computer runs presented various combinations imposed rotation mean magnetic field. There five separate cases turbulence: Case I, no or field; II, where only imposed; III, IV, vector field direction aligned; V, nonaligned directions. Dynamic coefficients predicted by statistical mechanics zero-mean random variables, but largest-scale coherent structures emerge all during transition; this implies dynamo action inherent These expected occur Cases II not III V; future studies will determine whether they persist.