KTH/Nordita/SU seminar in Theoretical Physics

Magnetic fields of cosmic bodies - generated and maintained by dynamos

by Karl-Heinz Rädler (Astrophysical Institute Potsdam)

Europe/Stockholm
FA31

FA31

Description
It is generally believed that most of the magnetic fields observed on cosmic bodies are due to dynamo processes, that is, are a consequence of the motion of electrically conducting fluid matter in their interiors. The dynamo proved to be one of the basic phenomena in cosmic physics. In the talk some fundamentals of dynamo theory will be explained. Its kinematic version is based on Maxwell's equations, whereas the full theory considers also the hydrodynamic equations. After discussing some general aspects of dynamo theory particular attention will be paid to the mean-field concept, which proved to be useful in many applications. In the last decades dynamo models for various specific cosmic bodies have been elaborated. In addition, some laboratory experiments on dynamos have successfully run. Examples for that will be elucidated.