  A magnetically-structured accretion disk corona, generated by buoyancy
instability in the disk, can account for observations of flare--like events in
Active Galactic Nuclei. We examine how Petschek magnetic reconnection,
associated with MHD turbulence, can result in a violent release of energy and
heat the magnetically closed regions of the corona up to canonical X-ray
emitting temperatures. X-ray magnetic flares, the after effect of the energy
released in slow shocks, can account for the bulk of the X-ray luminosity from
Seyfert galaxies and consistently explain the observed short-timescale
variability.
