Following recent evidence that the vortices in decaying two-dimensional turbulence can be classified into small mobile and large quasistationary, this paper examines the evidence that the latter might be considered a crystal whose formation embodies the inverse cascade of energy towards larger scales. Several diagnostics of order are applied to the ostensibly disordered large vortices. It is shown that their geometric arrangement is substantially more regular than random, that they move more slowly than could be expected from simple mean-field arguments, and that their energy is significantly lower than in a random reorganization of the same vortices. This is traced to screening of long-range interactions by the preferential association of vortices of opposite sign and it is argued that this is due to the mutual capture of corotating vortices, in a mechanism closer to tidal disruption than to electrostatic screening. Finally, the possible relation of these stochastic crystals to fixed points of the dynamical system representation of the turbulence flow is briefly examined.

中文翻译：

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二维湍流中的集体组织与筛选

根据最近的证据表明衰减二维湍流中的涡流可以分为小型移动和大型准稳态，本文研究了后者可能被视为晶体的证据，其形成体现了能量向更大规模的逆级联。几种有序诊断适用于表面上无序的大漩涡。结果表明，它们的几何排列比随机排列更规则，它们的移动速度比简单平均场参数所预期的要慢，并且它们的能量明显低于相同涡旋的随机重组。这可以追溯到相反符号涡旋的优先关联对长程相互作用的筛选，并且有人认为这是由于同向涡旋的相互捕获，在更接近潮汐破坏而不是静电屏蔽的机制中。最后，简要研究了这些随机晶体与湍流动力学系统表示的不动点之间的可能关系。