dorsal/arxiv
View SchemaFully developed turbulent dynamo at low magnetic Prandtl numbers
| Authors | Rodion Stepanov, Franck Plunian |
|---|---|
| Categories | |
| ArXiv ID | physics/0701152 |
| URL | https://arxiv.org/abs/physics/0701152 |
Abstract
We investigate the dynamo problem in the limit of small magnetic Prandtl number ($\Pm$) using a shell model of magnetohydrodynamic turbulence. The model is designed to satisfy conservation laws of total energy, cross helicity and magnetic helicity in the limit of inviscid fluid and null magnetic diffusivity. The forcing is chosen to have a constant injection rate of energy and no injection of kinetic helicity nor cross helicity. We find that the value of the critical magnetic Reynolds number ($\Rm$) saturates in the limit of small $\Pm$. Above the dynamo threshold we study the saturated regime versus $\Rm$ and $\Pm$. In the case of equipartition, we find Kolmogorov spectra for both kinetic and magnetic energy except for wave numbers just below the resistive scale. Finally the ratio of both dissipation scales (viscous to resistive) evolves as $\Pm^{-3/4}$ for $\Pm < 1$
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"abstract": "We investigate the dynamo problem in the limit of small magnetic Prandtl\nnumber ($\\Pm$) using a shell model of magnetohydrodynamic turbulence. The model\nis designed to satisfy conservation laws of total energy, cross helicity and\nmagnetic helicity in the limit of inviscid fluid and null magnetic diffusivity.\nThe forcing is chosen to have a constant injection rate of energy and no\ninjection of kinetic helicity nor cross helicity. We find that the value of the\ncritical magnetic Reynolds number ($\\Rm$) saturates in the limit of small\n$\\Pm$. Above the dynamo threshold we study the saturated regime versus $\\Rm$\nand $\\Pm$. In the case of equipartition, we find Kolmogorov spectra for both\nkinetic and magnetic energy except for wave numbers just below the resistive\nscale. Finally the ratio of both dissipation scales (viscous to resistive)\nevolves as $\\Pm^{-3/4}$ for $\\Pm \u003c 1$",
"arxiv_id": "physics/0701152",
"authors": [
"Rodion Stepanov",
"Franck Plunian"
],
"categories": [
"physics.flu-dyn",
"physics.plasm-ph"
],
"title": "Fully developed turbulent dynamo at low magnetic Prandtl numbers",
"url": "https://arxiv.org/abs/physics/0701152"
},
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