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Galactic dynamo and helicity losses through fountain flow

Authors :
Kandaswamy Subramanian
Axel Brandenburg
Dmitry Sokoloff
Anvar Shukurov
Source :
Astronomy & Astrophysics. 448:L33-L36
Publication Year :
2006
Publisher :
EDP Sciences, 2006.

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.<br />4 pages, 2 figures, accepted by A&A Letters

Details

ISSN :
14320746 and 00046361
Volume :
448
Database :
OpenAIRE
Journal :
Astronomy & Astrophysics
Accession number :
edsair.doi.dedup.....f374675e51b04f4dbc6d96be200836e4
Full Text :
https://doi.org/10.1051/0004-6361:200600011