Magnetic field amplification via protostellar disc dynamos

We numerically investigate the generation of a magnetic field in a protostellar disc via an alpha Omega-dynamo and the resulting magnetohydrodynamic (MHD) driven outflows. We find that for small values of the dimensionless dynamo parameter alpha(d), the poloidal field grows exponentially at a rate sigma proportional to Omega(K)root alpha(d), before saturating to a value proportional to root alpha(d). The dynamo excites dipole and octupole modes, but quadrupole modes are suppressed, because of the symmetries of the seed field. Initial seed fields too weak to launch MHD outflows are found to grow sufficiently to launch winds with observationally relevant mass fluxes of the order of 10(-9) M-circle dot yr(-1) for T Tauri stars. This suggests that alpha Omega-dynamos may be responsible for generating magnetic fields strong enough to launch observed outflows.