Saturation of the turbulent dynamo

摘要: The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed via turbulent motions on small spatial scales and subsequently transporting energy to larger scales. This process is known as dynamo depends properties turbulence, i.e., hydrodynamical Reynolds number compressibility gas, diffusivity. While we know growth rate linear regime, saturation level, ratio kinetic that reached, not from analytical calculations. In this paper present a scale-dependent model based an effective resistivity which determined turnover time scale eddies density. increases compared Spitzer value spectrum at its maximum moves ends when peak reaches characteristic wave k☆ critical number. level also type turbulence differs for limits large Prandtl numbers Pm. With our find levels between 43.8% 1.3% Pm≫1 2.43% 0.135% Pm≪1, where higher values refer incompressible lower ones highly compressible turbulence.