Magnetic field reversals in an experimental turbulent dynamo

2007/01/06 by Michaël Berhanu, Romain Monchaux, Berhanu, M. +25 · 5 citations
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Geomagnetism and Paleomagnetism Studies #Magnetic and Electromagnetic Effects #Solar and Space Plasma Dynamics

paper · pdf · doi:10.48550/arxiv.physics/0701076

openalex publication_date 2007/01/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

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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