MHD一様乱流の非等方化機構 : 第2報, Coherent微細渦とLorentz力

Fine scale structure in MHD homogeneous turbulence is investigated to clarify the relationship between anisotropy and coherent fine scale structure in turbulence. In MHD turbulence, mean diameter of the coherent fine scale eddy is about 10 times of Kolmogorov micro scale and maximum azimuthal velocity is about 0.7 times of umrs, which coincide with those in homogeneous isotropic turbulence, turbulent mixing layer and turbulent channel flows without magnetic field. Effect of magnetic field appears in angle distribution of axis of the coherent fine scale eddy. The coherent fine scale eddy perpendicular to the mean magnetic field decays fast due to strong Lorentz force, which results in anisotropic behaviors of MHD homogeneous turbulence.