Abstract
Observations suggest that magnetic fields play a dominant role in the internal dynamics of molecular cloud cores. As much of the magnetic field threading the cores must be lost before they can collapse to form stars, field loss is thought to be an important factor in controlling the rate of star formation.
We present models of the detailed process of magnetic field loss. These have implications for the overall rate of field loss, the origin of the random motions observed within cloud cores and the treatment of ambipolar diffusion in numerical simulations.
