MAGNETIC ACTIVITY IN THICK ACCRETION DISKS AND ASSOCIATED OBSERVABLE PHENOMENA .1. FLUX EXPULSION

We study the dynamics of toroidal magnetic flux tubes, symmetric about the rotation axis, inside nonmagnetic thick accretion disks around bl ack holes. We present model equations which include effects of gravity , centrifugal force, pressure gradient force, Coriolis force, drag, ma gnetic tension, and magnetic buoyancy. We solve them assuming the disk to be adiabatic. We show that under a wide range of parameters descri bing the size and the field strength, as well as angular momentum dist ribution inside the disk, buoyant flux tubes, either released on the e quatorial plane or at the outer edge of the disk, can gather in the ch imney-like openings near the axis. This behavior makes the chimneys ma gnetically most active and could shed light on the origin and accelera tion of cosmic jets, as well as the variabilities observed in blazars.