Change search
ReferencesLink to record
Permanent link

Direct link
Nonlinear Small-scale Dynamos at Low Magnetic Prandtl Numbers
Stockholm University, Faculty of Science, Department of Astronomy.
2011 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 741, no 2, 92- p.Article in journal (Refereed) Published
Abstract [en]

Saturated small-scale dynamo solutions driven by isotropic non-helical turbulence are presented at low magnetic Prandtl numbers Pr M down to 0.01. For Pr M < 0.1, most of the energy is dissipated via Joule heat and, in agreement with earlier results for helical large-scale dynamos, kinetic energy dissipation is shown to diminish proportional to Pr1/2 M down to values of 0.1. In agreement with earlier work, there is, in addition to a short Golitsyn k -11/3 spectrum near the resistive scale, also some evidence for a short k -1 spectrum on larger scales. The rms magnetic field strength of the small-scale dynamo is found to depend only weakly on the value of Pr M and decreases by about a factor of two as Pr M is decreased from 1 to 0.01. The possibility of dynamo action at Pr M = 0.1 in the nonlinear regime is argued to be a consequence of a suppression of the bottleneck seen in the kinetic energy spectrum in the absence of a dynamo and, more generally, a suppression of kinetic energy near the dissipation wavenumber.

Place, publisher, year, edition, pages
2011. Vol. 741, no 2, 92- p.
Keyword [en]
magnetohydrodynamics: MHD, turbulence
National Category
Astronomy, Astrophysics and Cosmology
URN: urn:nbn:se:su:diva-70041DOI: 10.1088/0004-637X/741/2/92ISI: 000296771500025OAI: diva2:478719
Available from: 2012-01-16 Created: 2012-01-16 Last updated: 2012-01-29Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Brandenburg, Axel
By organisation
Department of Astronomy
In the same journal
Astrophysical Journal
Astronomy, Astrophysics and Cosmology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 15 hits
ReferencesLink to record
Permanent link

Direct link