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Nonlinear Dynamo in a Disk Galaxy

Published online by Cambridge University Press:  19 July 2016

A. Poezd ,
A. Shukurov  and
D.D. Sokoloff
A. Poezd
Affiliation:
Physics Department, Moscow University, Moscow 119899, Russia
A. Shukurov
Affiliation:
Computing Center, Moscow University, Moscow 119899, Russia
D.D. Sokoloff
Affiliation:
Physics Department, Moscow University, Moscow 119899, Russia

Abstract

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A nonlinear thin-disk galactic dynamo model based on α-quenching is proposed. Assuming that the mean helicity depends on the magnetic field strength averaged across the disk, we derive a universal form of nonlinearity in the radial dynamo equation. We discuss the evolution of the regular magnetic field in the Milky Way and the Andromeda Nebula. It is argued that the reversals of the regular magnetic field in the Galaxy are a relic inherited from the structure of the seed field. We also briefly discuss the role of the turbulent diamagnetism and the effects of galactic evolution on the dynamo.

Keywords

Nonlinear galactic dynamosMagnetic field reversalsNonlinear transients
Type
8. Magnetic Fields in Galaxies: Dynamo Theory
Information
Symposium - International Astronomical Union , Volume 157: The Cosmic Dynamo , 1993 , pp. 349 - 353
Copyright
Copyright © Kluwer 1993 

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