MHD Accretion-Ejection Flows

In this proceeding I present recent works dealing with magnetohydrodynamic (MHD) simulations describing resistive accretion disks continuously launching large-scale, self-collimated MHD jets. In particular, I discuss the physical conditions required to produce these outflows and the related numerical issues. As an illustration I also present axisymmetric MHD numerical simulations of such accretion-ejection engines, demonstrating the mechanism controlling these flows.