Volume 87, Number 3, August 2009
Article Number 39002
Number of page(s) 5
Section Geophysics, Astronomy and Astrophysics
Published online 27 August 2009
EPL, 87 (2009) 39002
DOI: 10.1209/0295-5075/87/39002

A numerical model of the VKS experiment

C. 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