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| Paper: |
Modelling unstable accretion discs |
| Volume: |
261, The Physics of Cataclysmic Variables and Related Objects |
| Page: |
416 |
| Authors: |
Murray, J. R.; Truss, M. R.; Wynn, G. A. |
| Abstract: |
In the last few years great progress has been made in the hydrodynamic modelling of accretion discs. This paper summarises several key results. We have introduced into our hydrodynamic code a simple parametrisation of the dwarf nova thermal instability. This has enabled us to present the first two dimensional simulations of dwarf nova outbursts, SU UMa superoutbursts, and the outbursts of X-ray transients. Previous authors modelling outbursts with one dimensional codes have been forced to parametrise tidal forces on the disc, and cannot distinguish features such as spiral shocks. One dimensional simulations also produce very regular outbursts. With our two dimensional simulations we are able to more faithfully reproduce the variations in observed outbursts. Advances in computer power make three dimensional disc simulations feasible as well. We show the first simulations of a disc in a close binary responding to an out of the plane torque. The disc develops a solid body warp that precesses retrogradely in the inertial frame, with a periodicity consistent with negative superhumps. |
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