Dallas V, Alexakis A
Laboratoire de Physique Statistique, École normale supérieure, CNRS, Université Pierre et Marié Curie, Université Paris Diderot, 24 rue Lhomond, 75005 Paris, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Nov;88(5):053014. doi: 10.1103/PhysRevE.88.053014. Epub 2013 Nov 18.
We investigate the origins of k(-2) spectrum in a decaying Taylor-Green magnetohydrodynamic flow with zero large scale magnetic flux that was reported by Lee et al. [Phys. Rev. E 81, 016318 (2010)]. So far, a possible candidate for this scaling exponent has been the weak turbulence phenomenology. From our numerical simulations, we observe that current sheets in the magnetic Taylor-Green flow are formed in regions of magnetic discontinuities. Based on this observation and by studying the influence of the current sheets on the energy spectrum, using a filtering technique, we argue that the discontinuities are responsible for the -2 power law scaling of the energy spectra of this flow.
我们研究了Lee等人[《物理评论E》81, 016318 (2010)]报道的具有零大尺度磁通量的衰减泰勒 - 格林磁流体动力学流中(k^{-2})谱的起源。到目前为止，这个标度指数的一个可能候选者是弱湍流现象学。从我们的数值模拟中，我们观察到磁泰勒 - 格林流中的电流片形成于磁不连续区域。基于这一观察，并通过研究电流片对能谱的影响，使用一种滤波技术，我们认为不连续性是该流能谱(-2)幂律标度的原因。
