English

Accretion and plasma outflow from dissipationless discs

Astrophysics 2010-04-28 v1

Abstract

We consider an extreme case of disc accretion onto a gravitating centre when the viscosity in the disc is negligible. The angular momentum and the rotational energy of the accreted matter is carried out by a magnetized wind outflowing from the disc. The outflow of matter from the disc occurs due to the Blandford & Payne(1982) centrifugal mechanism. The disc is assumed to be cold. Accretion and outflow are connected by the conservation of the energy, mass and the angular momentum. The basic properties of the outflow, angular momentum flux and energy flux per particle in the wind, do not depend on the details of the structure of the accretion disc. In the case of selfsimilar accretion/outflow, the dependence of the rate of accretion M˙\dot M in the disc depends on the disc radius rr on the law M˙r12(α21)\dot M \sim r^{{1\over2(\alpha^2-1)}}, where α\alpha is a dimensionless Alfvenic radius. In the case of α1\alpha \gg 1, the accretion in the disc is provided by very weak matter outflow from the disc and the outflow predominantly occurs from the very central part of the disc. The solution obtained in the work provides mechanism which transforms the gravitational energy of the accreted matter into the energy of the outflowing wind with efficiency close to 100%. The final velocity can essentially exceed Kepler velocity at the site of the wind launch. This mechanism allows us to understand the nature of the astrophysical objects with low luminosity discs and energetic jet-like outflows.

Keywords

Cite

@article{arxiv.0809.0429,
  title  = {Accretion and plasma outflow from dissipationless discs},
  author = {Sergei Bogovalov and Stanislav Kelner},
  journal= {arXiv preprint arXiv:0809.0429},
  year   = {2010}
}

Comments

Submitted to MNRAS

R2 v1 2026-06-21T11:16:05.892Z