ON THE DYNAMICS OF WARPED ACCRETION DISKS

We present some analyses of warping modes in inviscid near Keplerian d isks taking the three-dimensional structure fully into account. The re sults of this investigation verify the validity of a vertical averagin g approximation for thin disks when the radial wavelength is significa ntly longer than the disk thickness. They also indicate that long wave length disturbances may persist for long times. Shorter wavelength dis turbances in non-self-gravitating disks are found to propagate with li ttle dispersion at a speed related to the sound speed. When self-gravi ty becomes important fast and slow waves are found which also propagat e with little dispersion. When a small viscosity is included the evolu tion of the disturbances becomes more diffusive in character as descri bed in previous work.