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Vortices in Thin, Compressible, Unmagnetized Disks

Bryan M. Johnson·Charles F. Gammie
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Abstract

We consider the formation and evolution of vortices in a hydrodynamic shearing-sheet model. The evolution is done numerically using a version of the ZEUS code. Consistent with earlier results, an injected vorticity field evolves into a set of long-lived vortices, each of which has a radial extent comparable to the local scale height. But we also find that the resulting velocity field has a positive shear stress, . This effect appears only at high resolution. The transport, which decays with time as t^-1/2, arises primarily because the vortices drive compressive motions. This result suggests a possible mechanism for angular momentum transport in low-ionization disks, with two important caveats: a mechanism must be found to inject vorticity into the disk, and the vortices must not decay rapidly due to three-dimensional instabilities.

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Bryan M. Johnson, Charles F. Gammie. 2006-04-03. Vortices in Thin, Compressible, Unmagnetized Disks. https://doi.org/10.1086/497358

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