Low magnetic Prandtl number dynamos with helical forcing
نویسندگان
چکیده
منابع مشابه
Nonlinear dynamos at infinite magnetic Prandtl number.
The dynamo instability is investigated in the limit of infinite magnetic Prandtl number. In this limit the fluid is assumed to be very viscous so that the inertial terms can be neglected and the flow is enslaved to the forcing. The forcing consist of an external forcing function that drives the dynamo flow and the resulting Lorentz force caused by the back reaction of the magnetic field. The fl...
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Using simulations of helically driven turbulence, it is shown that the ratio of kinetic to magnetic energy dissipation scales with the magnetic Prandtl number in power law fashion with an exponent of approximately 0.6. Over six orders of magnitude in the magnetic Prandtl number the magnetic field is found to be sustained by large-scale dynamo action of alphasquared type. This work extends a sim...
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Using direct simulations of hydromagnetic turbulence driven by random polarized waves it is shown that dynamo action is possible over a wide range of magnetic Prandtl numbers from 10−3 to 1. Triply periodic boundary conditions are being used. In the final saturated state the resulting magnetic field has a large-scale component of Beltrami type. For the kinematic phase, growth rates have been de...
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Dynamo action in a fully helical Beltrami (ABC) flow is studied using both direct numerical simulations and subgrid modeling. Sufficient scale separation is given in order to allow for largescale magnetic energy build-up. Growth of magnetic energy obtains down to a magnetic Prandtl number PM = RM/RV close to 0.005, where RV and RM are the kinetic and magnetic Reynolds numbers. The critical magn...
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The onset of dynamo action is investigated within the context of a newly developed low Rossby, low magnetic Prandtl number, convection-driven dynamo model. This multiscale model represents an asymptotically exact form of an α^{2} mean field dynamo model in which the small-scale convection is represented explicitly by finite amplitude, single mode solutions. Both steady and oscillatory convectio...
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ژورنال
عنوان ژورنال: Physical Review E
سال: 2005
ISSN: 1539-3755,1550-2376
DOI: 10.1103/physreve.72.056320