Kleeorin Nathan, Rogachevskii Igor
Department of Mechanical Engineering, The Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Feb;67(2 Pt 2):026321. doi: 10.1103/PhysRevE.67.026321. Epub 2003 Feb 27.
An effect of rotation on a developed turbulent stratified convection is studied. Dependences of the hydrodynamic helicity, the alpha tensor, and the effective drift velocity of the mean magnetic field on the rate of rotation and an anisotropy of turbulent convection are found. It is shown that in an anisotropic turbulent convection the alpha effect can change its sign depending on the rate of rotation. The evolution of the alpha effect is much more complicated than that of the hydrodynamic helicity in an anisotropic turbulent convection of a rotating fluid. Different properties of the effective drift velocity of the mean magnetic field in a rotating turbulent convection are found: (i) a poloidal effective drift velocity can be diamagnetic or paramagnetic depending on the rate of rotation; (ii) there is a difference in the effective drift velocities for the toroidal and poloidal magnetic fields; (iii) a toroidal effective drift velocity can play a role of an additional differential rotation. The above effects and an effect of a nonzero divergence of the effective drift velocity of the toroidal magnetic field on a magnetic dynamo in a developed turbulent stratified convection of a rotating fluid are studied. Astrophysical applications of the obtained results are discussed.
研究了旋转对充分发展的湍流分层对流的影响。发现了流体动力学螺旋度、α张量以及平均磁场的有效漂移速度与旋转速率和湍流对流各向异性的依赖关系。结果表明,在各向异性湍流对流中,α效应会根据旋转速率改变其符号。在旋转流体的各向异性湍流对流中,α效应的演化比流体动力学螺旋度的演化要复杂得多。发现了旋转湍流对流中平均磁场有效漂移速度的不同性质:(i) 极向有效漂移速度根据旋转速率可以是抗磁性的或顺磁性的;(ii) 环形磁场和极向磁场的有效漂移速度存在差异;(iii) 环形有效漂移速度可以起到附加差动旋转的作用。研究了上述效应以及环形磁场有效漂移速度的非零散度对旋转流体充分发展的湍流分层对流中磁发电机的影响。讨论了所得结果的天体物理应用。