The Riga Dynamo Experiment

Cosmic magnetic fields, including the magnetic field of the Earth,are produced by the homogeneous dynamo effect in moving electricallyconducting fluids. We sketch the history of the underlying theoryand comment on previous attempts to realize homogeneous dynamos inthe laboratory. For the main part, we report on two series ofexperiments carried out at the Riga dynamo facility. In November1999 a slowly growing magnetic field eigenmode was observed forthe first time in a liquid metal experiment. In July 2000, themagnetic field saturation regime was studied and a number ofinteresting back-reaction effects were observed. A preliminaryinterpretation of the measured data is also presented.