Outwards transport of angular momentum in a shallow water accretion disk experiment

Abstract

Accretion disks are a ubiquitous phenomenon in astrophysics. To be consistent with observations, there must be an as yet unknown mechanism for angular momentum redistribution. In laboratory experiments, especially, the two-dimensional geometry and the magnetohydrodynamic characteristics of an accretion disk are difficult to reproduce. Here we propose the design of a shallow water experiment in accretion disk geometry, where differential rotation is induced in a quasi-two-dimensional shallow water layer with an open surface that allows direct measurement of the radial and azimuthal fluid dynamics. The effect of the magnetic field is mimicked by established equivalence of magnetohydrodynamic and viscoelastic fluids. We demonstrate radial outwards transport of angular momentum in an accretion disk laboratory experiment. Therefore, the proposed experimental setup can help us to identify the origin of angular momentum redistribution in accretion disks.