Bistability between a stationary and an oscillatory dynamo in a turbulent flow of liquid sodium

M. Berhanu; B. Gallet; R. Monchaux; M. Bourgoin; Ph Odier; J. F. Pinton; N. Plihon; R. Volk; S. Fauve; N. Mordant; F. Ptrlis; S. Aumaître; A. Chiffaudel; F. Daviaud; B. Dubrulle; F. Ravelet

doi:10.1017/S0022112009991996

Bistability between a stationary and an oscillatory dynamo in a turbulent flow of liquid sodium

M. Berhanu, B. Gallet, R. Monchaux, M. Bourgoin, Ph Odier, J. F. Pinton, N. Plihon, R. Volk, S. Fauve, N. Mordant, F. Ptrlis, S. Aumaître, A. Chiffaudel, F. Daviaud, B. Dubrulle, F. Ravelet

Research output: Contribution to journal › Article › peer-review

Abstract

We report the first experimental observation of a bistable dynamo regime. A turbulent flow of liquid sodium is generated between two disks in the von Krmn geometry (VKS experiment). When one disk is kept at rest, bistability is observed between a stationary and an oscillatory magnetic field. The stationary and oscillatory branches occur in the vicinity of a codimension-two bifurcation that results from the coupling between two modes of magnetic field. We present an experimental study of the two regimes and study in detail the region of bistability that we understand in terms of dynamical system theory. Despite the very turbulent nature of the flow, the bifurcations of the magnetic field are correctly described by a low-dimensional model. In addition, the different regimes are robust; i.e. turbulent fluctuations do not drive any transition between the oscillatory and stationary states in the region of bistability.

Original language	English
Pages (from-to)	217-226
Number of pages	10
Journal	Journal of Fluid Mechanics
Volume	641
DOIs	https://doi.org/10.1017/S0022112009991996
Publication status	Published - 1 Jan 2009
Externally published	Yes

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Berhanu, M., Gallet, B., Monchaux, R., Bourgoin, M., Odier, P., Pinton, J. F., Plihon, N., Volk, R., Fauve, S., Mordant, N., Ptrlis, F., Aumaître, S., Chiffaudel, A., Daviaud, F., Dubrulle, B., & Ravelet, F. (2009). Bistability between a stationary and an oscillatory dynamo in a turbulent flow of liquid sodium. Journal of Fluid Mechanics, 641, 217-226. https://doi.org/10.1017/S0022112009991996

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title = "Bistability between a stationary and an oscillatory dynamo in a turbulent flow of liquid sodium",

abstract = "We report the first experimental observation of a bistable dynamo regime. A turbulent flow of liquid sodium is generated between two disks in the von Krmn geometry (VKS experiment). When one disk is kept at rest, bistability is observed between a stationary and an oscillatory magnetic field. The stationary and oscillatory branches occur in the vicinity of a codimension-two bifurcation that results from the coupling between two modes of magnetic field. We present an experimental study of the two regimes and study in detail the region of bistability that we understand in terms of dynamical system theory. Despite the very turbulent nature of the flow, the bifurcations of the magnetic field are correctly described by a low-dimensional model. In addition, the different regimes are robust; i.e. turbulent fluctuations do not drive any transition between the oscillatory and stationary states in the region of bistability.",

author = "M. Berhanu and B. Gallet and R. Monchaux and M. Bourgoin and Ph Odier and Pinton, \{J. F.\} and N. Plihon and R. Volk and S. Fauve and N. Mordant and F. Ptrlis and S. Auma{\^i}tre and A. Chiffaudel and F. Daviaud and B. Dubrulle and F. Ravelet",

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doi = "10.1017/S0022112009991996",

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Berhanu, M, Gallet, B, Monchaux, R, Bourgoin, M, Odier, P, Pinton, JF, Plihon, N, Volk, R, Fauve, S, Mordant, N, Ptrlis, F, Aumaître, S, Chiffaudel, A, Daviaud, F, Dubrulle, B & Ravelet, F 2009, 'Bistability between a stationary and an oscillatory dynamo in a turbulent flow of liquid sodium', Journal of Fluid Mechanics, vol. 641, pp. 217-226. https://doi.org/10.1017/S0022112009991996

TY - JOUR

T1 - Bistability between a stationary and an oscillatory dynamo in a turbulent flow of liquid sodium

AU - Berhanu, M.

AU - Gallet, B.

AU - Monchaux, R.

AU - Bourgoin, M.

AU - Odier, Ph

AU - Pinton, J. F.

AU - Plihon, N.

AU - Volk, R.

AU - Fauve, S.

AU - Mordant, N.

AU - Ptrlis, F.

AU - Aumaître, S.

AU - Chiffaudel, A.

AU - Daviaud, F.

AU - Dubrulle, B.

AU - Ravelet, F.

PY - 2009/1/1

Y1 - 2009/1/1

N2 - We report the first experimental observation of a bistable dynamo regime. A turbulent flow of liquid sodium is generated between two disks in the von Krmn geometry (VKS experiment). When one disk is kept at rest, bistability is observed between a stationary and an oscillatory magnetic field. The stationary and oscillatory branches occur in the vicinity of a codimension-two bifurcation that results from the coupling between two modes of magnetic field. We present an experimental study of the two regimes and study in detail the region of bistability that we understand in terms of dynamical system theory. Despite the very turbulent nature of the flow, the bifurcations of the magnetic field are correctly described by a low-dimensional model. In addition, the different regimes are robust; i.e. turbulent fluctuations do not drive any transition between the oscillatory and stationary states in the region of bistability.

AB - We report the first experimental observation of a bistable dynamo regime. A turbulent flow of liquid sodium is generated between two disks in the von Krmn geometry (VKS experiment). When one disk is kept at rest, bistability is observed between a stationary and an oscillatory magnetic field. The stationary and oscillatory branches occur in the vicinity of a codimension-two bifurcation that results from the coupling between two modes of magnetic field. We present an experimental study of the two regimes and study in detail the region of bistability that we understand in terms of dynamical system theory. Despite the very turbulent nature of the flow, the bifurcations of the magnetic field are correctly described by a low-dimensional model. In addition, the different regimes are robust; i.e. turbulent fluctuations do not drive any transition between the oscillatory and stationary states in the region of bistability.

U2 - 10.1017/S0022112009991996

DO - 10.1017/S0022112009991996

M3 - Article

AN - SCOPUS:76349095780

SN - 0022-1120

VL - 641

SP - 217

EP - 226

JO - Journal of Fluid Mechanics

JF - Journal of Fluid Mechanics

ER -

Bistability between a stationary and an oscillatory dynamo in a turbulent flow of liquid sodium

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