The effects of vertical outflows on disk dynamos
Department of Mathematics, University of Newcastle, Newcastle upon Tyne NE1 7RU, UK
2 Nordita, Blegdamsvej 17, 2100 Copenhagen, Denmark
Corresponding author: A. Bardou, Anne.Bardou@ncl.ac.uk
Accepted: 15 February 2001
We consider the effect of vertical outflows on the mean-field dynamo in a thin disk. These outflows could be due to winds or magnetic buoyancy. We analyse both two-dimensional finite-difference numerical solutions of the axisymmetric dynamo equations and a free-decay mode expansion using the thin-disk approximation. Contrary to expectations, a vertical velocity can enhance dynamo action, provided the velocity is not too strong. In the nonlinear regime this can lead to super-exponential growth of the magnetic field.
Key words: accretion, accretion disks / magnetic fields / galaxies: magnetic fields
© ESO, 2001