The von Kármán Sodium experiment: Turbulent dynamical dynamos

Romain Monchaux, Michael Berhanu, Sébastien Aumaître, Arnaud Chiffaudel, François Daviaud, Bérengère Dubrulle, Florent Ravelet, Stephan Fauve, Nicolas Mordant, François Pétrélis, Mickael Bourgoin, Philippe Odier (+3 others)
2009 Physics of Fluids  
The von Kármán Sodium ͑VKS͒ experiment studies dynamo action in the flow generated inside a cylinder filled with liquid sodium by the rotation of coaxial impellers ͑the von Kármán geometry͒. We first report observations related to the self-generation of a stationary dynamo when the flow forcing is R -symmetric, i.e., when the impellers rotate in opposite directions at equal angular velocities. The bifurcation is found to be supercritical with a neutral mode whose geometry is predominantly
more » ... predominantly axisymmetric. We then report the different dynamical dynamo regimes observed when the flow forcing is not symmetric, including magnetic field reversals. We finally show that these dynamics display characteristic features of low dimensional dynamical systems despite the high degree of turbulence in the flow.
doi:10.1063/1.3085724 fatcat:76556tnc7zgajbryn4ikrranq4