Physical Review E - Statistical, Nonlinear, and Soft Matter Physics
We present direct numerical simulations and α-model simulations of four familiar three-dimensional magnetohydrodynamic (MHD) turbulence effects: selective decay, dynamic alignment, inverse cascade of magnetic helicity, and the helical dynamo effect. The MHD α model is shown to capture the long-wavelength spectra in all these problems, allowing for a significant reduction of computer time and memory at the same kinetic and magnetic Reynolds numbers. In the helical dynamo, not only does the α model correctly reproduce the growth rate of magnetic energy during the kinematic regime, it also captures the nonlinear saturation level and the late generation of a large scale magnetic field by the helical turbulence.
Mininni, Pablo D.; Montgomery, David C.; and Pouquet, Annick, "Numerical Solutions of the Three-Dimensional Magnetohydrodynamic Α Model" (2005). Open Dartmouth: Faculty Open Access Scholarship. 1995.