Have we understood the Riga dynamo?

The experimental campaigns at the Riga sodium facility, carried out from November 1999 until recently, have brought about a wealth of data on the kinematic and the saturation regime of this hydromagnetic dynamo. In the kinematic regime, the measured growth rates and frequencies of the eigenfield differ from the numerical predictions only by a few per cent. A qualitative understanding of the saturation regime can be well achieved within a simple one-dimensional model of downward braking of the azimuthal velocity component by the Lorentz forces. This model can be refined by taking into account the Lorentz force driven flow in the outermost cylinder. We summarize our present understanding of the Riga experiment, and comment on some open questions.