Magnetic Fields play a key role in the physics of star formation on all scales: from the formation of the large complexes of molecular clouds to the formation of solar-like planetary systems. The plasma physics involved is non-linear and very complex, which requires the development of large numerical codes. An additional difficulty is that the detection and study of magnetic fields is not easy from an observational point of view, and therefore theoretical models cannot easily be constrained.

In the week from April 21st to 25th in 2003, a meeting was held on the Campus of the...