A possible mechanism for the formation of molecular flows

The results of 2.5-dimensional MHD simulations modelling flows from a protostar are considered; the finite conductivity of the material is taken into account, The flows arise during the dynamical interaction of the matter accreting onto the protostar and the circumstellar disk with an ordered poloidal magnetic field frozen into the disk, The calculations show that some part of the accreting matter is accelerated above the central parts of the disk, forming a well-collimated bipolar flow perpendicular to the disk surface, The acceleration of matter from the disk surface is due to the gas pressure gradient. Moving at supersonic velocities along the magnetic field lines of force. the outflowing matter is collimated by the magnetic and gas pressure gradients, Up to 20% of the matter accreted leaves the system, The kinematic and physical flow parameters are consistent with those observed in real molecular flows from star-forming regions.