Non-Stationary Discs and Instabilities
Abstract
We review our current knowledge of thermal and viscous instabilities in accretion discs around compact objects. We begin with classical disc models based on analytic viscosity prescriptions, discussing physical uncertainties and exploring time-dependent solutions of disc evolution. We also review the ionization instability responsible for outbursting dwarf nova and X-ray binary systems, including some detailed comparisons between alpha-based models and the observed characteristics of these systems. We then review modern theoretical work based on ideas around angular momentum transport mediated by magnetic fields, focusing in particular on knowledge gained through local and global computer simulations of MHD processes in discs. We discuss how magnetohydrodynamics (MHD) may alter our understanding of outbursts in white dwarf and X-ray binary systems. Finally, we turn to the putative thermal/viscous instabilities that were predicted to exist in the inner, radiation pressure-dominated regions of black hole and neutron star discs, in apparent contradiction to the observed stability of the high/soft state in black hole X-ray binaries.
Cite
@article{arxiv.2505.04402,
title = {Non-Stationary Discs and Instabilities},
author = {Omer Blaes and Yan-Fei Jiang and Jean-Pierre Lasota and Galina Lipunova},
journal= {arXiv preprint arXiv:2505.04402},
year = {2025}
}
Comments
55 pages, 8 figures. We thank the International Space Science Institute in Bern for hosting a workshop on the first 50 years of research on accretion discs. This version has been accepted for publication but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available at http://dx.doi.org/10.1007/s11214-025-01245-8