AAS Meeting #193 - Austin, Texas, January 1999
Session 119. Low-Luminoisty AGN and Black Holes
Oral, Saturday, January 9, 1999, 2:00-3:30pm, Room 8 (A,B,C)

## [119.02] The Origin of Galactic and Metagalactic Magnetic Fields: The Black Hole Accretion Disk Dynamo

S. Colgate, H. Li (LANL), H. Beckley (NMIMT), J. Finn (LANL), V. Pariev (U. Arizona; LANL)

The frequent star-disk collisions in the accretion disk forming the massive black hole of galaxies is an efficient, robust mechanism for generating the \alpha-helicity in the \alpha-\Omega dynamo. In the rotating frame of the disk, these collisions result in axially directed, expanding plumes which "un-twist" due to their increased moment of inertia. We have demonstrated this flow field and its feasibility in the laboratory in preparation for a dynamo experiment using liquid sodium. The near-infinite number of rotations of the inner accretion disk and hence, amplification, ensures that this dynamo will saturate at the maximum accretion disk stress, where Bmax~50 kG, corresponding to a luminosity, L ~1046 ergs/s. The magnetic flux expelled as a collimated Poynting flux is sufficient to explain the magnetic flux of the galaxy as well as that of galactic clusters. The dissipation of a fraction of this magnetic energy is the likely source of the AGN/quasar phenomena.