Three-dimensional MHD simulations of molecular cloud fragmentation regulated by gravity, ambipolar diffusion, and turbulence

We find that the star formation is accelerated by the supersonic turbulence in the magnetically dominated (subcritical) clouds. We employ a fully three-dimensional simulation to study the role of magnetic fields and ion-neutral friction in regulating gravitationally driven fragmentation of molecular clouds. The time-scale of collapsing core formation in subcritical clouds is a few ×10⁷ years when starting with small subsonic perturbations. However, it is shortened to approximately several ×10⁶ years by the supersonic flows in the clouds. We confirm that higher-spacial resolution simulations also show the same result.