Magnetically Advected Winds

Observations of X-ray absorption lines in magnetically driven disc winds around black hole binaries and active galactic nuclei yield a universal radial density profile r(sup -1.2) in the wind. This is in disagreement with the standard Blandford and Payne profile BP r(sup -1.5) expected when the magnetic field is neither advected nor diffusing through the accretion disc. In order to account for this discrepancy, we establish a new paradigm for magnetically driven astrophysical winds according to which the large-scale ordered magnetic field that threads the disc is continuously generated by the Cosmic Battery around the inner edge of the disc and continuously diffuses outward. We obtain self-similar solutions of such magnetically advected winds (MAW) and discuss their observational ramifications