Magnetic helicity evolution in a periodic domain with imposed field.

摘要: In helical hydromagnetic turbulence with an imposed magnetic field (which is constant in space and time) the helicity of within a periodic domain no longer invariant ideal equations. Alternatively, there generalized that It shown this quantity not gauge it can therefore be used practice. Instead, evolution equation describing deviation from to useful tool. demonstrated tool determine steady state quenching alpha-effect. A simple three-scale model derived describe predict its sign as function strength. The results agree favorably simulations.