Amplification of Primordial Magnetic Fields by Anisotropic Gravitational Collapse

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dc.creatorKing, Emma J.
dc.creatorColes, Peter
dc.date2005-08-17
dc.date.accessioned2026-07-07T06:25:08Z
dc.date.available2026-07-07T06:25:08Z
dc.descriptionIf a magnetic field is frozen into a plasma that undergoes spherical compression then the magnetic field B varies with the plasma density ρaccording to B \propto ρ^{2/3}. In the gravitational collapse of cosmological density perturbations, however, quasi-spherical evolution is very unlikely. In anisotropic collapses the magnetic field can be a much steeper function of gas density than in the isotropic case. We investigate the distribution of amplifications in realistic gravitational collapses from Gaussian initial fluctuations using the Zel'dovich approximation. Representing our results using a relation of the form B\propto ρ^α, we show that the median value of αcan be much larger than the α=2/3 resulting from spherical collapse, even if there is no initial correlation between magnetic field and principal collapse directions. These analytic arguments go some way towards understanding the results of numerical simulations.
dc.description9 pages, 4 figures. Submitted to MNRAS
dc.identifierhttps://arxiv.org/abs/astro-ph/0508370
dc.identifierhttp://arxiv.org/abs/astro-ph/0508370
dc.identifierMon.Not.Roy.Astron.Soc. 365 (2006) 1288-1294
dc.identifierdoi:10.1111/j.1365-2966.2005.09811.x
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/96761
dc.subjectAstrophysics
dc.titleAmplification of Primordial Magnetic Fields by Anisotropic Gravitational Collapse
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