Launching of accretion disc winds along dynamo-generated magnetic fields

The problem of magnetic field generation and advection in accretion discs i s considered, in the context of wind launching and angular momentum extract ion. A dipole-symmetry solution of the dynamo equations is found, with forc e-free boundary conditions appropriate for matching to a wind solution. Con sideration of the curved field geometry and diffusive nature of the disc en ables the position of the sonic point to be calculated and related to the f ield inclination at the disc surface. A critical inclination of 20 degrees to the horizontal results, for which the sonic point lies in the disc surfa ce and there is no potential barrier to wind launching. Hence the wind mass -loss rate will only become excessive, leading to disc disruption, for larg e field bending. The compressional effect of the horizontal magnetic field enhances the wind mass flux.