Magnetic field reversals in an experimental turbulent dynamo

M. Berhanu; R. Monchaux; S. Fauve; N. Mordant; F. Pétrélis; A. Chiffaudel; F. Daviaud; B. Dubrulle; L. Marié; F. Ravelet; M. Bourgoin; Ph Odier; J. F. Pinton; R. Volk

doi:10.1209/0295-5075/77/59001

Magnetic field reversals in an experimental turbulent dynamo

M. Berhanu, R. Monchaux, S. Fauve, N. Mordant, F. Pétrélis, A. Chiffaudel, F. Daviaud, B. Dubrulle, L. Marié, F. Ravelet, M. Bourgoin, Ph Odier, J. F. Pinton, R. Volk

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Abstract

We report the first experimental observation of reversals of a dynamo field generated in a laboratory experiment based on a turbulent flow of liquid sodium. The magnetic field randomly switches between two symmetric solutions B and -B. We observe a hierarchy of time scales similar to the Earth's magnetic field: the duration of the steady phases is widely distributed, but is always much longer than the time needed to switch polarity. In addition to reversals we report excursions. Both coincide with minima of the mechanical power driving the flow. Small changes in the flow driving parameters also reveal a large variety of dynamo regimes.

Original language	English
Article number	59001
Journal	EPL
Volume	77
Issue number	5
DOIs	https://doi.org/10.1209/0295-5075/77/59001
Publication status	Published - 1 Mar 2007
Externally published	Yes

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title = "Magnetic field reversals in an experimental turbulent dynamo",

abstract = "We report the first experimental observation of reversals of a dynamo field generated in a laboratory experiment based on a turbulent flow of liquid sodium. The magnetic field randomly switches between two symmetric solutions B and -B. We observe a hierarchy of time scales similar to the Earth's magnetic field: the duration of the steady phases is widely distributed, but is always much longer than the time needed to switch polarity. In addition to reversals we report excursions. Both coincide with minima of the mechanical power driving the flow. Small changes in the flow driving parameters also reveal a large variety of dynamo regimes.",

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T1 - Magnetic field reversals in an experimental turbulent dynamo

AU - Berhanu, M.

AU - Monchaux, R.

AU - Fauve, S.

AU - Mordant, N.

AU - Pétrélis, F.

AU - Chiffaudel, A.

AU - Daviaud, F.

AU - Dubrulle, B.

AU - Marié, L.

AU - Ravelet, F.

AU - Bourgoin, M.

AU - Odier, Ph

AU - Pinton, J. F.

AU - Volk, R.

PY - 2007/3/1

Y1 - 2007/3/1

N2 - We report the first experimental observation of reversals of a dynamo field generated in a laboratory experiment based on a turbulent flow of liquid sodium. The magnetic field randomly switches between two symmetric solutions B and -B. We observe a hierarchy of time scales similar to the Earth's magnetic field: the duration of the steady phases is widely distributed, but is always much longer than the time needed to switch polarity. In addition to reversals we report excursions. Both coincide with minima of the mechanical power driving the flow. Small changes in the flow driving parameters also reveal a large variety of dynamo regimes.

AB - We report the first experimental observation of reversals of a dynamo field generated in a laboratory experiment based on a turbulent flow of liquid sodium. The magnetic field randomly switches between two symmetric solutions B and -B. We observe a hierarchy of time scales similar to the Earth's magnetic field: the duration of the steady phases is widely distributed, but is always much longer than the time needed to switch polarity. In addition to reversals we report excursions. Both coincide with minima of the mechanical power driving the flow. Small changes in the flow driving parameters also reveal a large variety of dynamo regimes.

U2 - 10.1209/0295-5075/77/59001

DO - 10.1209/0295-5075/77/59001

M3 - Article

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SN - 0295-5075

VL - 77

JO - EPL

JF - EPL

IS - 5

M1 - 59001

ER -

Magnetic field reversals in an experimental turbulent dynamo

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