Magnetically driven jets and winds: Exact solutions

Abstract

We present a general class of self-similar solutions of the full set of MHD equations that include matter flow, electromagnetic fields, pressure, and gravity. The solutions represent axisymmetric, time- independent, nonrelativistic, ideal, magnetohydrodynamic, collimated outflows (jets and winds) from magnetized accretion disks around compact objects. The magnetic field extracts angular momentum from the disk, accelerates the outflows perpendicular to the disk, and provides collimation at large distances. The terminal outflow velocities are of the order of or greater than the rotational velocity of the disk at the base of the flow. When a nonzero electric current flows along the jet, the outflow radius oscillates with axial distance, whereas when the total electric current is zero (with the return current flowing across the jet's cross section), the outflow radius increases to a maximum and then decreases. The method can also be applied to relativistic outflows.