Abstract
Observational evidence exists which suggests that magnetic fields are capable of providing support to molecular clouds thereby impeding their collapse long enough for fragmentation to occur. But is the field of the star-forming cloud preserved in the cores and if not how quickly does a core become distinct? Recent observations of the Barnard 1 cloud in Perseus from SCUBA at the James Clerk Maxwell Telescope (JCMT) reveal that each core exhibits a different mean magnetic field direction which in all cases but one is distinct from the field of the ambient cloud. On the contrary observations in Orion using the JCMT and high-resolution polarimetry from the Berkeley-Illinois-Maryland Association (BIMA) interferometer reveal a core which has apparently preserved the magnetic field of the parent filamentary cloud to very small scales. We will discuss the implications of these data in terms of the ambipolar diffusion rate of low-mass cores and the strength of the core magnetic field as inferred from the dispersion of the polarization data