A numerical model of the VKS experimentC. J. P. Gissinger
Laboratoire de Physique Statistique and Laboratoire de Radiostronomie, École Normale Supérieure CNRS 24 rue Lhomond, F-75005 Paris, France, EU
received 11 June 2009; accepted in final form 23 July 2009; published August 2009
published online 27 August 2009
We present numerical simulations of the magnetic field generated by the flow of liquid sodium driven by two counter-rotating impellers (VKS experiment). Using a kinematic code in cylindrical geometry, it is shown that different magnetic modes can be generated depending on the flow configuration. While the time-averaged axisymmetric mean flow generates an equatorial dipole, our simulations show that an axial field of either dipolar or quadrupolar symmetry can be generated by taking into account non-axisymmetric components of the flow. Moreover, we show that by breaking a symmetry of the flow, the magnetic field becomes oscillatory. This leads to reversals of the axial dipole polarity, involving a competition with the quadrupolar component.
91.25.Cw - Origins and models of the magnetic field; dynamo theories.
47.65.-d - Magnetohydrodynamics and electrohydrodynamics.
© EPLA 2009