Broken Symmetry and Coherent Structure in MHD Turbulence

Absolute equilibrium ensemble theory for ideal homogeneous magnetohydrodynamic (MHD) turbulence is fairly well developed [1]. Theory and simulation indicate that ideal MHD turbulence is non-ergodic and contains coherent structure. The question of applicability to real ({\it i.e.}, dissipative) MHD turbulence is examined. Results from several very long time numerical simulations on a $64^3$ grid are presented. It is seen that coherent structure begins to form before decay dominates over nonlinearity. The connection with inverse spectral cascades and selective decay will also be discussed.\\ \mbox{[1]} J. V. Shebalin, {\it J.\ Plasma Phys.}, {\bf 72}, 507-524, 2006.