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| Turbulent accretion disk density. |
From the AAS Nova post, the image shows the density of a turbulent accretion disk in one of the first in-depth, three-dimensional magnetohydrodynamic simulations of a thin disk threaded by a large-scale vertical magnetic field. Accretion disks — which include everything from protoplanetary disks to disks around supermassive black holes — are notoriously challenging to model. Both small-scale turbulence and large-scale magnetic fields are thought to be critical processes governing motions within the disk, accretion of material, and launching of disk outflows — but capturing both of these different scales simultaneously in simulations is very difficult. The image above shows computations by Zhaohuan Zhu (University of Nevada, Las Vegas) and James Stone (Princeton University) that span three orders of magnitude in radius, extend all the way to the pole, and are evolved for more than 1,000 innermost orbits. The behavior the authors find is widely applicable to many different kinds of accretion disk systems.
