The Saturation Regime of the Riga Dynamo Experiment: Observational Facts and their Interpretation

In the Riga dynamo experiment, a helical flow with a velocity up to 15 m/s is produced by a motor driven propeller. This flow is free enough to be modified by the Lorentz forces in a non-trivial manner.
In addition to the increase of the necessary motor power due to the axial components of the Lorentz force, we observed a significant deformation of the magnetic field structure and a shift of the eigenvalue. Both observations can be explained by the downward accumulating brake effect of the azimuthal Lorentz force component.
The occurence of a triple frequency in the magnetic field spectrum gives indications for the action of the non-axisymmetric parts of the Lorentz forces on the flow.