Magnetic dynamo action at low magnetic Prandtl numbers
arXiv:1011.0202 · doi:10.1103/PhysRevLett.105.215002
Abstract
Amplification of magnetic field due to kinematic turbulent dynamo action is studied in the regime of small magnetic Prandtl numbers. Such a regime is relevant for planets and stars interiors, as well as for liquid metal laboratory experiments. A comprehensive analysis based on the Kazantsev-Kraichnan model is reported, which establishes the dynamo threshold and the dynamo growth rates for varying kinetic helicity of turbulent fluctuations. It is proposed that in contrast with the case of large magnetic Prandtl numbers, the kinematic dynamo action at small magnetic Prandtl numbers is significantly affected by kinetic helicity, and it can be made quite efficient with an appropriate choice of the helicity spectrum.
4 pages, 3 figures, accepted to Physical Review Letters
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- On the Nature of Magnetic Turbulence in Rotating, Shearing Flows
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- Simulations of the kinematic dynamo onset of spherical Couette flows with smooth and rough boundaries
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- Virtual states and exponential decay in small-scale dynamo