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
Service de Physique de l'Etat Condensé, Direction des Sciences de la Matière, CEA-Saclay, CNRS URA 2464, 91191 Gif-sur-Yvette cedex, France.
Phys Rev Lett. 2007 Jan 26;98(4):044502. doi: 10.1103/PhysRevLett.98.044502. Epub 2007 Jan 25.
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.
我们报告了在冯·卡门钠实验中对发电机效应的观测，即通过液态钠的强烈湍流涡旋流产生磁场。对磁场的平均部分和波动部分都进行了研究。发电机阈值对应于磁雷诺数R(m)约为30。在流动横向边界处，高于阈值30%时观测到了约40 G量级的平均磁场。对于其中两个分量，均方根波动大于相应的平均值。将均方磁场的标度与先前对高雷诺数流动所做的预测进行了比较。
