AIP astronomy picture of the month

Interior of the vessel for the Karlruhe dynamo experiment
(credit: K.-H. Rädler, AIP )

It is generally believed that the magnetic fields of the Earth and the planets, of the Sun and other stars as well as those of galaxies are due to dynamo action of fluid motions. After many years of preparations large laboratory experiments showing the dynamo effect in a volume of liquid sodium have run successfully at two places, in Riga (Latvia) and in Karlsruhe (Germany), at the end of 1999. The picture shows a part of the dynamo module of the Karlsruhe experiment, a cylindrical vessel of about 1 m radius and 1 m height with sodium flowing through a system of channels. With sufficiently high flow rates magnetic fields are excited and maintained. A number of contributions to the theory of the Karlsruhe experiment and estimates of the self-excitation conditions were delivered by the MHD Group of the AIP.

( credit: K.-H. Rädler, AIP ).