Reduction of velocity fluctuations in a turbulent flow of gallium by an external magnetic field.
The magnetic field of planets or stars is generated by the motion of a conducting fluid through a dynamo instability. The saturation of the magnetic field occurs through the reaction of the Lorentz force on the flow. In relation to this phenomenon, we study the effect of a magnetic field on a turbulent flow of liquid gallium. The measurement of electric potential differences provides a signal related to the local velocity fluctuations. We observe a reduction of velocity fluctuations at all frequencies in the spectrum when the magnetic field is increased.
Berhanu
Michael
M
Laboratoire de Physique Statistique, Ecole Normale Supérieure & CNRS, 24 Rue Lhomond, 75231 Paris Cedex 05, France. mberhanu@lps.ens.fr
Gallet
Basile
B
Mordant
Nicolas
N
Fauve
Stéphan
S