ABSTRACT
Year 2000 was marked by the success of the dynamo experiments of Riga and Karlsruhe. In both cases, a saturated magnetic field of a few milliTeslas was produced. These successes crown years of efforts of the two teams during which the experiments were planned, built and tested. In both cases, more than a cubic meter of liquid sodium is used and the flow is driven into a well-defined configuration with powers in excess of 100 kW. The configurations were chosen to mimic known kinematic dynamos, thus enabling a good prediction of the onset of dynamo action. These experiments demonstrate the feasibility of laboratory dynamos and open the way to a second generation of experiments, in which the flow will have more freedom to organize itself under the combined actions of the forcing and of the Lorentz force. It will also be interesting to explore the effect of the Coriolis force and to unravel the characteristics of turbulence in these dynamos. All these dynamo experiments nicely complement the numerical models now available because they allow the exploration of regimes with low magnetic Prandtl number and high Reynolds number.
