| Description: | Recent years have been marked by a notable change in the star formation paradigm. Instead of quasi-static molecular clouds slowly evolving under the influence of gravity and ambipolar diffusion a new picture with more action and dynamics emerged. Within new understanding of interstellar processes, the molecular clouds are associated with turbulent density fluctuations and the structure of the interstellar medium evolves fast on the sound crossing times. However, these simulations are unable to reproduce correctly the dynamics of magnetic fields on scales of the created molecular clouds, in particular magnetic flux removal. We show that a process termed by us "reconnection diffusion" is responsible for removing magnetic flux from molecular clouds. For the giant molecular clouds (GMCs) and for many cloud cores the resulting rates of magnetic field removal dominate the ambipolar diffusion rates in partially ionized gas. Our numerical simulations validate the concept of "reconnection diffusion" and substantially modify the understanding of the role of magnetic fields in star formation. |
