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| Titel |
Direct numerical simulations of helical dynamo action: MHD and beyond |
| VerfasserIn |
D. O. Gómez, P. D. Mininni |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 11, no. 5/6 ; Nr. 11, no. 5/6 (2004-12-03), S.619-629 |
| Datensatznummer |
250008992
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| Publikation (Nr.) |
 copernicus.org/npg-11-619-2004.pdf |
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| Zusammenfassung |
| Magnetohydrodynamic dynamo action is often invoked to explain the
existence of magnetic fields in several astronomical objects. In this
work, we present direct numerical simulations of MHD helical dynamos, to
study the exponential growth and saturation of magnetic fields. Simulations
are made within the framework of incompressible flows and using periodic
boundary conditions. The statistical properties of the flow are studied, and it
is found that its helicity displays strong spatial fluctuations. Regions
with large kinetic helicity are also strongly concentrated in space,
forming elongated structures. In dynamo simulations using these flows,
we found that the growth rate and the saturation level of magnetic
energy and magnetic helicity reach an asymptotic value as the Reynolds
number is increased. Finally, extensions of the MHD theory to include
kinetic effects relevant in astrophysical environments are discussed. |
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