The origin of the magnetic fields of the universe: The plasma astrophysicsof the free energy of the universe

The interpretation of Faraday rotation measure maps of active galactic nucl ei (AGNs) within galaxy clusters has revealed ordered or coherent regions, L(mag)similar to 50-100 kpc (similar to 3x10(23) cm), that are populated wi th large, similar to 30 muG magnetic fields. The magnetic energy of these c oherent regions is L-mag(3)(B-2/8 pi)similar to 10(59-60) ergs, and the tot al magnetic energy over the whole cluster (similar to1 Mpc across) is expec ted to be even larger. Understanding the origin and role of these magnetic fields is a major challenge to plasma astrophysics. A sequence of physical processes that are responsible for the production, redistribution, and diss ipation of these magnetic fields is proposed. These fields are associated w ith single AGNs within the cluster and therefore with all galaxies during t heir AGN (active galactic nucleus or quasar) phase, simply because only the central supermassive black holes (similar to 10(8)M) formed during the AGN phase have an accessible energy of formation, similar to 10(61) ergs, that can account for the magnetic field energy budget. An alpha-Omega dynamo pr ocess has been proposed that operates in an accretion disk around a black h ole. The disk rotation naturally provides a large winding number, similar t o 10(11) turns, sufficient to make both large gain and large flux. The heli city of the dynamo can be generated by the differential plume rotation deri ved from star-disk collisions. This helicity generation process has been de monstrated in the laboratory and the dynamo gain was simulated numerically. A liquid sodium analog of the dynamo is being built. Speculations are that the back reaction of the saturated dynamo will lead to the formation of a force-free magnetic helix, which will carry the energy and flux of the dyna mo away from the accretion disk and redistribute the field within the clust ers and galaxy walls. The magnetic reconnection of a small fraction of this energy logically is the source of the AGN (active galactic nucleus or quas ar) luminosity, and the remainder of the field energy should then dominate the free energy of the present-day universe. The reconnection of this inter galactic field during a Hubble time is the only sufficient source of energy necessary to produce an extragalactic cosmic ray energy spectrum as observ ed in this galaxy, and at the same time allow this spectrum to escape to th e galaxy voids faster than the GZK (blackbody radiation) loss. (C) 2001 Ame rican Institute of Physics.