Magnetic-field generation in Kolmogorov turbulence.
Magnetic-field generation in Kolmogorov turbulence.
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柯尔莫哥洛夫湍流中的磁场产生。
DOI：
10.1103/physrevlett.92.144501
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发表时间：
2003
影响因子：
8.6
通讯作者：
F. Cattaneo
中科院分区：
文献类型：
--
作者：
S. Boldyrev;F. Cattaneo
我们分析了初始的，运动学阶段的磁场演化在各向同性和均匀的湍流导电流体与粗糙的速度场，v（l）约l（α），α <1。该机制与具有小磁普兰特数的流体中的磁场产生问题有关，即，欧姆电阻率远大于粘度。我们建议，较小的粗糙度指数α，较大的磁雷诺数，需要激发磁场波动。这意味着数值或实验研究的磁流体动力学湍流小普朗特数需要达到极高的分辨率，以充分描述磁现象。
We analyze the initial, kinematic stage of magnetic field evolution in an isotropic and homogeneous turbulent conducting fluid with a rough velocity field, v(l) approximately l(alpha), alpha<1. This regime is relevant to the problem of magnetic field generation in fluids with small magnetic Prandtl number, i.e., with Ohmic resistivity much larger than viscosity. We propose that the smaller the roughness exponent alpha, the larger the magnetic Reynolds number that is needed to excite magnetic fluctuations. This implies that numerical or experimental investigations of magnetohydrodynamic turbulence with small Prandtl numbers need to achieve extremely high resolution in order to describe magnetic phenomena adequately.