Ab initio simulations of accretion disc boundary layers
Abstract
I discuss the results of simplified three dimensional magnetohydrodynamic simulations of the boundary layer between a disc and a non-rotating, unmagnetized star. Strong magnetic fields, possibly approaching equipartition with the thermal energy, occur in the boundary layer due to the shearing of disc-generated fields. The mean boundary layer magnetic field, which is highly variable on an orbital timescale, is estimated to exceed 50 kG for a CV with an accretion rate of 10^(-9) solar masses per year. However, these fields do not drive efficient angular momentum transport within the boundary layer. As a consequence the radial velocity in the boundary layer is low, and the density high.
Cite
@article{arxiv.astro-ph/0110250,
title = {Ab initio simulations of accretion disc boundary layers},
author = {Philip J. Armitage},
journal= {arXiv preprint arXiv:astro-ph/0110250},
year = {2007}
}
Comments
To appear in "The Physics of Cataclysmic Variables and Related Objects", eds. B. Gaensicke, K. Beuermann & K. Reinsch. Animations from boundary layer and black hole plunging region simulations at http://star-www.st-and.ac.uk/~pja3/movies.html