Spotted Disks

Abstract

Rotating, turbulent cosmic fluids are generally pervaded by coherent structures such as vortices and magnetic flux tubes. The formation of such structures is a robust property of rotating turbulence as has been confirmed in computer simulations and laboratory experiments. We defend here the notion that accretion disks share this feature of rotating cosmic bodies. In particular, we show that the intense shears of Keplerian flows do not inhibit the formation of vortices. Given suitable initial disturbances and high enough Reynolds numbers, long-lived vortices form in Keplerian shear flows and analogous magnetic structures form in magnetized disks. The formation of the structures reported here should have significant consequences for the transport properties of disks and for the observed properties of hot disks.