Generation of magnetic field by combined action of turbulence and shear.
Generation of magnetic field by combined action of turbulence and shear.
复制标题
通过湍流和剪切的联合作用产生磁场。
DOI：
10.1103/physrevlett.100.184501
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发表时间：
2007
影响因子：
8.6
通讯作者：
J. McWilliams
中科院分区：
文献类型：
--
作者：
Tarek Ahmed Yousef;T. Heinemann;A. Schekochihin;N. Kleeorin;I. Rogachevskii;A. Iskakov;A. Iskakov;A. Iskakov;S. Cowley;S. Cowley;J. McWilliams
在细长剪切盒中数值研究了非螺旋湍流中叠加线性剪切的平均场发电机的可行性。在比湍流外尺度大得多的尺度上，磁场呈指数增长，其特征尺度为lB比例S（-1/2），增长率为γ比例S，其中S为剪切率。这种新发现的剪切发电机效应可能代表了一个非常通用的机制，在广泛的一类天体物理系统中产生大规模的磁场与空间相干的平均流量。
The feasibility of a mean-field dynamo in nonhelical turbulence with a superimposed linear shear is studied numerically in elongated shearing boxes. Exponential growth of the magnetic field at scales much larger than the outer scale of the turbulence is found. The characteristic scale of the field is lB proportional S(-1/2) and the growth rate is gamma proportional S, where S is the shearing rate. This newly discovered shear dynamo effect potentially represents a very generic mechanism for generating large-scale magnetic fields in a broad class of astrophysical systems with spatially coherent mean flows.