Fluctuation dynamo and turbulent induction at low magnetic Prandtl numbers
| Autor: | Michael R. E. Proctor, Steven Cowley, Alexander Schekochihin, Tarek A. Yousef, Alexey B. Iskakov, James C. McWilliams |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Physics
Magnetic energy Astrophysics (astro-ph) Prandtl number Fluid Dynamics (physics.flu-dyn) FOS: Physical sciences General Physics and Astronomy Reynolds number Magnetic Reynolds number Physics - Fluid Dynamics Mechanics Astrophysics Nonlinear Sciences - Chaotic Dynamics Physics - Plasma Physics Physics::Geophysics Plasma Physics (physics.plasm-ph) Physics::Fluid Dynamics symbols.namesake Dynamo theory symbols Magnetic Prandtl number Chaotic Dynamics (nlin.CD) Magnetohydrodynamics Dynamo |
| DOI: | 10.1088/1367-2630/9/8/300 |
| Popis: | This paper is a detailed report on a programme of simulations used to settle a long-standing issue in the dynamo theory and demonstrate that the fluctuation dynamo exists in the limit of large magnetic Reynolds number Rm>>1 and small magnetic Prandtl number Pm<1. The stability curve Rm_c(Re) (and, it is argued, the nature of the dynamo) is substantially different from the case of the simulations and liquid-metal experiments with a mean flow. It is not as yet possible to determine numerically whether the growth rate is ~Rm^{1/2} in the limit Re>>Rm>>1, as should be the case if the dynamo is driven by the inertial-range motions. The magnetic-energy spectrum in the low-Pm regime is qualitatively different from the Pm>1 case and appears to develop a negative spectral slope, although current resolutions are insufficient to determine its asymptotic form. At 1 Comment: IoP latex, 27 pages, 25 figures, 3 tables. Accepted by New J. Physics |
| Databáze: | OpenAIRE |
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