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Galactic dynamo and helicity losses through fountain flow
- 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
- Subjects :
- Physics
Advection
Astrophysics::High Energy Astrophysical Phenomena
Astrophysics (astro-ph)
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Helicity
Magnetic field
Physics::Fluid Dynamics
Nonlinear system
Space and Planetary Science
Magnetic helicity
Quantum electrodynamics
Turbulence kinetic energy
Astrophysics::Galaxy Astrophysics
Equipartition theorem
Dynamo
Subjects
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