2002/07/31 by Vladislav Zheligovsky, V. A. Zheligovsky, Olga Podvigina +1 · 1 citation
Biochemistry, Genetics and Molecular Biology · Engineering · Physics and Astronomy · #Fluid Dynamics and Turbulent Flows #Geomagnetism and Paleomagnetism Studies #Micro and Nano Robotics #nlin.CD #physics.flu-dyn
paper · pdf · doi:10.1080/0309192032000101676
published as Geophys. Astrophys. Fluid Dynamics, 97, 2003, 225-248 · 24 pages, 7 figures. This is the final version of the manuscript (1 reference added and linguistic corrections made). Accepted in Geophysical and Astrophysical Fluid Dynamics
arxiv created 2003/04/01 · openalex publication_date 2003/06/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study generation of magnetic fields involving large spatial scales by time- and space-periodic short-scale parity-invariant flows. The anisotropic magnetic eddy diffusivity tensor is calculated by the standard procedure involving expansion of magnetic modes and their growth rates in power series in the scale ratio. Our simulations, conducted for flows with random harmonic composition and exponentially decaying energy spectra, demonstrate that for a substantial part of time-periodic flows magnetic eddy diffusivity is negative for molecular diffusivity above the instability threshold for short-scale magnetic field generation. Thus, like it was in the case of steady flows, enlargement of the spatial scale of magnetic field is shown to be beneficial for generation by time-periodic flows. However, they are less efficient dynamos, than steady flows.