141 citations · 572 across the 31 of their papers we have counts for
19 papers · 1 filter
Fast and Furious dynamo action in the anisotropic dynamo
Franck Plunian, Thierry Alboussière
In the limit of large magnetic Reynolds numbers, it is shown that a smooth differential rotation can lead to fast dynamo action, provided that the electrical conductivity or magnet…
Inverse cascade of energy in helical turbulence
Franck Plunian, Andrei Teimurazov, Rodion Stepanov +1
Using direct numerical simulation of hydrodynamic turbulence with helicity forcing applied at all scales, a near-maximum helical turbulent state is obtained, with an inverse energy…
Transition from large-scale to small-scale dynamo
Yannick Ponty, Franck Plunian
The dynamo equations are solved numerically with a helical forcing corresponding to the Roberts flow. In the fully turbulent regime the flow behaves as a Roberts flow on long time…
Enstrophy transfers in helical turbulence
Shubhadeep Sadhukhan, Roshan Samuel, Franck Plunian +3
In this paper we study the enstrophy transers in helical turbulence using direct numerical simulation. We observe that the helicity injection does not have significant effects on t…
On uniqueness of transfer rates in magnetohydrodynamic turbulence
Franck Plunian, Rodion Stepanov, Mahendra Kumar Verma
In hydrodynamic and magnetohydrodynamic turbulence, expressions for the transfer rates rely on integrals over wavenumber triads satisfying . As…
Axisymmetric dynamo action is possible with anisotropic conductivity
Franck Plunian, Thierry Alboussière
A milestone of dynamo theory is Cowling's theorem, known in its modern form as the impossibility for an axisymmetric velocity field to generate an axisymmetric magnetic field by dy…
Energy transfers in MHD turbulence and its applications to dynamo
Mahendra K. Verma, Rodion Stepanov, Franck Plunian
In this paper we describe the mode-to-mode energy transfers and energy fluxes of MHD turbulence. These energy transfers are very useful for understanding the turbulence dynamics, a…
Non-Kolmogorov cascade of helicity driven turbulence
Mouloud Kessar, Franck Plunian, Rodion Stepanov +1
We solve the Navier-Stokes equations with two simultaneous forcings. One forcing is applied at a given large-scale and it injects energy. The other forcing is applied at all scales…
Shell Models of Magnetohydrodynamic Turbulence
Franck Plunian, Rodion Stepanov, Peter Frick
Shell models of hydrodynamic turbulence originated in the seventies. Their main aim was to describe the statistics of homogeneous and isotropic turbulence in spectral space, using…
Experimental evidence of Alfvén wave propagation in a Gallium alloy
Thierry Alboussiere, Philippe Cardin, François Debray +5
Experiments with a liquid metal alloy, galinstan, are reported and show clear evidence of Alfvén wave propagation as well as resonance of Alfvén modes. Galinstan is liquid at room…
Cascades and dissipation ratio in rotating MHD turbulence at low magnetic Prandtl number
Franck Plunian, Rodion Stepanov
A phenomenology of isotropic magnetohydrodynamic turbulence subject to both rotation and applied magnetic field is presented. It is assumed that the triple correlations decay-time…
Generation of axisymmetric modes in cylindrical kinematic mean-field dynamos of VKS type
A. Giesecke, C. Nore, F. Plunian +6
In an attempt to understand why the dominating magnetic field observed in the von-Kármán-Sodium (VKS) dynamo experiment is axisymmetric, we investigate in the present paper the abi…
Harmonic and subharmonic solutions of the Roberts dynamo problem. Application to the Karlsruhe experiment
F. Plunian, K. -H. Radler
Two different approaches to the Roberts dynamo problem are considered. Firstly, the equations governing the magnetic field are specified to both harmonic and subharmonic solutions…
Influence of electromagnetic boundary conditions onto the onset of dynamo action in laboratory experiments
R. Avalos-Zuniga, F. Plunian
We study the onset of dynamo action of the Riga and Karlsruhe experiments with the addition of an external wall, the electro-magnetic properties of which being different from those…
An optimal scale separation for a dynamo experiment
Franck Plunian
Scale separation between the flow and the magnetic field is a common feature of natural dynamos. It has also been used in the Karlsruhe sodium experiment in which the scale of the…
Impact of impellers on the axisymmetric magnetic mode in the VKS2 dynamo experiment
R. Laguerre, C. Nore, A. Ribeiro +3
In the VKS2 (von Kármán Sodium 2) successful dynamo experiment of September 2006, the magnetic field that was observed showed a strong axisymmetric component, implying that non axi…
Parametric instability of the helical dynamo
Marine Peyrot, Franck Plunian, Christiane Normand
We study the dynamo threshold of a helical flow made of a mean (stationary) plus a fluctuating part. Two flow geometries are studied, either (i) solid body or (ii) smooth. Two well…
Fully developed turbulent dynamo at low magnetic Prandtl numbers
Rodion Stepanov, Franck Plunian
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 cons…
A non local shell model of turbulent dynamo
F. Plunian, R. Stepanov
We derive a new shell model of magnetohydrodynamic (MHD) turbulence in which the energy transfers are not necessary local. Like the original MHD equations, the model conserves the…