Current theoretical models for the outflows/jets from AGN, X-ray binaries and
young stellar objects involve large-scale magnetic fields threading an
underlying accretion disk. We suggest that such a disk is subjected to warping
instability and retrograde precession driven by magnetic torques associated
with the outflow. The growth timescale for the disk warp and the precession
period are of order the radial infall time of the disk. These effects may be
relevant to jet precession and other variabilities observed in many systems.Comment: 4 pages with 2 figures. ApJL in pres