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Lookup NU author(s): Fred Gent, Professor Anvar ShukurovORCiD, Dr Graeme Sarson, Dr Andrew Fletcher
This is the final published version of a letter that has been published in its final definitive form by Oxford University Press, 2013.
For re-use rights please refer to the publisher's terms and conditions.
The origin and structure of the magnetic fields in the interstellar medium of spiral galaxies isinvestigated with 3D, non-ideal, compressible magnetohydrodynamic simulations, includingstratification in the galactic gravity field, differential rotation and radiative cooling. A rectan-gular domain, 1×1×2 kpc3 in size, spans both sides of the galactic mid-plane. Supernovaexplosions drive transonic turbulence. A seed magnetic field grows exponentially to reach astatistically steady state within 1.6 Gyr. Following Germano (1992), we use volume averagingwith a Gaussian kernel to separate magnetic field into a mean field and fluctuations. Suchaveraging does not satisfy all Reynolds rules, yet allows a formulation of mean-field theory.The mean field thus obtained varies in both space and time. Growth rates differ for the mean-field and fluctuating field and there is clear scale separation between the two elements, whoseintegral scales are about 0.7 and 0.3 kpc, respectively.
Author(s): Gent FA, Shukurov A, Sarson GR, Fletcher A, Mantere MJ
Publication type: Letter
Publication status: Published
Journal: Monthly Notices of the Royal Astronomical Society
Year: 2013
Volume: 430
Issue: 1
Pages: L40-L44
Print publication date: 23/12/2013
ISSN (electronic): 1745-3933
Publisher: Oxford University Press
URL: http://dx.doi.org/10.1093/mnrasl/sls042
DOI: 10.1093/mnrasl/sls042
