Axial dipolar dynamo action in the Taylor-Green vortex

Abstract

We present a numerical study of the magnetic field generated by the Taylor-Green vortex. We show that periodic boundary conditions can be used to mimic realistic boundary conditions by prescribing the symmetries of the velocity and magnetic fields. This gives insight in some problems of central interest for dynamos: the possible effect of velocity fluctuations on the dynamo threshold, the role of boundary conditions on the threshold and on the geometry of the magnetic field generated by dynamo action. In particular, we show that an axial dipolar dynamo similar to the one observed in a recent experiment can be obtained with an appropriate choice of the symmetries of the magnetic field. The nonlinear saturation is studied and a simple model explaining the magnetic Prandtl number dependence of the super/sub critical nature of the dynamo transition is given.

References in corpus (5)

• Generation of magnetic field by dynamo action in a turbulent flow of liquid sodium
• On the magnetic fields generated by experimental dynamos
• Subcritical dynamo bifurcation in the Taylor Green flow
• Bypassing Cowling's theorem in axisymmetric fluid dynamos
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Cited by in corpus (7)

• Bistability and chaos in Taylor-Green dynamo
• Supercriticality to subcriticality in dynamo transitions
• Turbulent channel without boundaries: The periodic Kolmogorov flow
• Dynamo Action in a Quasi-Keplerian Taylor-Couette Flow
• Velocity and acceleration statistics in particle-laden turbulent swirling flows
• Dynamo transition in a five-mode helical model
• Discrete Symmetries in Dynamo Reversals