Magnetic Fields from Clouds to Stars (Bfields-2024)

The interstellar medium (ISM) is magnetized, and magnetic fields play a fundamental role in the growth of structures, leading to the formation of stars and their subsequent evolution. However, given the broad range of spatial scales and the combination of multiple physical processes involved at every evolutionary stage from clouds to stars, the relative importance of magnetic fields with respect to other forces is still not well described, neither observationally nor theoretically. 

The magnetic field strength increases by multiple orders of magnitude from molecular clouds (approx. microgauss) to dense star-forming cores to protostellar disks and to stars (approx. kilogauss). This variation, however, occurs at a much slower rate than the increase in density and decrease in size, implying that a significant fraction of the initial magnetic flux must be dissipated during the star formation process. The detailed physical processes governing the magnitude, geometry, and impact of magnetic fields at different scales remain to be understood.