Abstract

It is believed that magnetic fields play important roles in star formation processes, in particular to overcome both the angular momentum and magnetic flux problems. Polarimetry from the optical to the centimeter wavelengths has been the most powerful observing technique to study magnetic fields: in this Focus Meeting we wish to bring together communities working with polarimetric observations of the various stages and objects along the star formation sequence, from the structure of star-forming molecular clouds to the arrival of young stars on the zero-age main sequence. The goal is to discuss how to compare observations of magnetic fields at different evolutionary stages and physical scales such that we can establish a coherent view of their key role in the multi-scale process of star formation. Combining results from different fields is complex, and thus we will emphasize how different measurements of the magnetic fields can be compared and interpreted into a coherent picture despite widely varying observing techniques, and the very different objects and physical scales that are probed.