2011/01/31 by Joanne Mason, Leonid Malyshkin, Stanislav Boldyrev +2 · 21 citations
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · Physics and Astronomy · #Action (physics) #Classical mechanics #Dynamo #Dynamo theory #Flow (mathematics) #Geomagnetism and Paleomagnetism Studies #Geophysics and Gravity Measurements #Isotropy #Magnetic diffusivity #Magnetic field #Magnetohydrodynamics #Mechanics #Physics #Quantum mechanics #Solar and Space Plasma Dynamics #Statistical physics #astro-ph.GA #astro-ph.SR #nlin.CD #physics.flu-dyn #physics.plasm-ph
paper · pdf · doi:10.1088/0004-637x/730/2/86
published in The Astrophysical Journal 730(2), 86 (IOP Publishing)
arxiv created 2011/03/07 · openalex publication_date 2011/03/07 · arxiv updated 2011/03/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Hydromagnetic dynamo theory provides the prevailing theoretical description for the origin of magnetic fields in the universe. Here, we consider the problem of kinematic, small-scale dynamo action driven by a random, incompressible, non-helical, homogeneous, and isotropic flow. In the Kazantsev dynamo model, the statistics of the driving flow are assumed to be instantaneously correlated in time. Here, we compare the results of the model with the dynamo properties of a simulated flow that has similar spatial characteristics as the Kazantsev flow but different temporal statistics. In particular, the simulated flow is a solution of the forced Navier–Stokes equations and hence has a finite correlation time. We find that the Kazantsev model typically predicts a larger magnetic growth rate and a magnetic spectrum that peaks at smaller scales. However, we show that by filtering the diffusivity spectrum at small scales it is possible to bring the growth rates into agreement and simultaneously align the magnetic spectra.