Courvoisier Alice, Kim Eun-jin
Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Oct;80(4 Pt 2):046308. doi: 10.1103/PhysRevE.80.046308. Epub 2009 Oct 9.
We investigate how the addition of a large-scale steady motion, either shear or uniform flow, modifies the magnetic transport properties of a family of chaotic velocity fields with different correlation times. We compute numerically the kinematic alpha effect that those flows give rise to and show that it is reduced by the presence of a large-scale motion parallel to the large-scale magnetic field, except under certain conditions when it can be slightly enhanced via resonances. The alpha effect is shown to depend on the nature of the large-scale motion and on the temporal characteristics of the chaotic flow. These results highlight the strong influence that a shear or a uniform flow can have on the turbulent transport of magnetic fields.
我们研究了添加大规模稳定运动（剪切流或均匀流）如何改变具有不同相关时间的一系列混沌速度场的磁输运特性。我们通过数值计算了这些流所产生的运动学α效应，并表明，除了在某些条件下通过共振可使其略有增强外，与大规模磁场平行的大规模运动会使该效应减弱。结果表明，α效应取决于大规模运动的性质以及混沌流的时间特征。这些结果突出了剪切流或均匀流对磁场湍流输运可能产生的强烈影响。
