Stationary accretion disks launching super fast-magnetosonic MHD jets

Abstract

We present self-similar models of resistive viscous Keplerian disks driving non-relativistic magnetohydrodynamics (MHD) jets becoming super fast-magnetosonic. We show that in order to obtain such solutions, the thermal pressure must be a sizeable fraction of the poloidal magnetic pressure at the Alfven surface. These steady solutions which undergo a recollimation shock causally disconnected from the driving engine, account for structures with a high temperature plasma in the sub-Alfvenic region. We suggest that only unsteady outflows with typical time-scales of several disk dynamical time-scales can be produced if the suitable pressure conditions are not fulfilled.