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Galactic dynamo and helicity losses through fountain flow

Anvar Shukurov·Dmitry Sokoloff·Kandaswamy Subramanian·Axel Brandenburg
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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.

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Anvar Shukurov, Dmitry Sokoloff, Kandaswamy Subramanian, Axel Brandenburg. 2006-01-19. Galactic dynamo and helicity losses through fountain flow. https://doi.org/10.1051/0004-6361%3A200600011

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