Galactic dynamo and helicity losses through fountain flow
Astrophysics
2007-05-23 v2
Abstract
Nonlinear behaviour of galactic dynamos is studied, allowing for magnetic helicity removal by the galactic fountain flow. A suitable advection speed is estimated, and a one-dimensional mean-field dynamo model with dynamic alpha-effect is explored. It is shown that the galactic fountain flow is efficient in removing magnetic helicity from galactic discs. This alleviates the constraint on the galactic mean-field dynamo resulting from magnetic helicity conservation and thereby allows the mean magnetic field to saturate at a strength comparable to equipartition with the turbulent kinetic energy.
Cite
@article{arxiv.astro-ph/0512592,
title = {Galactic dynamo and helicity losses through fountain flow},
author = {Anvar Shukurov and Dmitry Sokoloff and Kandaswamy Subramanian and Axel Brandenburg},
journal= {arXiv preprint arXiv:astro-ph/0512592},
year = {2007}
}
Comments
4 pages, 2 figures, accepted by A&A Letters