Generation of a magnetic field by dynamo action in a turbulent flow of liquid sodium

We report the observation of dynamo action in the von Kármán sodium experiment, i.e., the generation of a magnetic field by a strongly turbulent swirling flow of liquid sodium. Both mean and fluctuating parts of the field are studied. The dynamo threshold corresponds to a magnetic Reynolds number R(...

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Published inPhysical review letters Vol. 98; no. 4; p. 044502
Main Authors Monchaux, R, Berhanu, M, Bourgoin, M, Moulin, M, Odier, Ph, Pinton, J-F, Volk, R, Fauve, S, Mordant, N, Pétrélis, F, Chiffaudel, A, Daviaud, F, Dubrulle, B, Gasquet, C, Marié, L, Ravelet, F
Format Journal Article
LanguageEnglish
Published United States 26.01.2007
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Summary:We report the observation of dynamo action in the von Kármán sodium experiment, i.e., the generation of a magnetic field by a strongly turbulent swirling flow of liquid sodium. Both mean and fluctuating parts of the field are studied. The dynamo threshold corresponds to a magnetic Reynolds number R(m) approximately 30. A mean magnetic field of the order of 40 G is observed 30% above threshold at the flow lateral boundary. The rms fluctuations are larger than the corresponding mean value for two of the components. The scaling of the mean square magnetic field is compared to a prediction previously made for high Reynolds number flows.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.98.044502