A method to quantify the energy transfer among turbulent structures using singular value decomposition (SVD) is presented. We apply the method to numerical turbulence data obtained from a global plasma simulation using the Hasegawa–Wakatani fluid model, in which the Kelvin–Helmholtz instability plays a dominant role. Using the SVD method, the electrostatic potential is decomposed into a background potential deformation, a zonal flow, a coherent mode and an intermittent structure. Thus there are four key structures, as distinct from the three found in conventional theory. The kinetic energy of each structure is evaluated, and the limit cycle among them is obtained. In the limit cycle, an abrupt change of the background is found to be synchronised with the period of the zonal flow. The energy transfer function of each turbulence structure, which is defined on the basis of a vorticity equation, is evaluated. This then provides physical understanding of how the limit cycle is sustained by dynamical changes in the energy transfer among structures over the its period. In addition, it is shown that the abrupt deformation of the background is caused by the non-linear self-coupling of the intermittent structure.

提出了一种利用奇异值分解（SVD）量化湍流结构之间能量传递的方法。我们将该方法应用于使用长谷川-若谷流体模型从全球等离子体模拟获得的数值湍流数据，其中开尔文-亥姆霍兹不稳定性起主要作用。使用SVD方法，静电势被分解为背景电势变形，地带流，相干模式和间歇结构。因此，有四个关键结构，不同于传统理论中的三个。评价每种结构的动能，并获得它们之间的极限循环。在极限循环中，背景的突然变化与纬向流的周期同步。每个湍流结构的能量传递函数，评估基于涡度方程定义的值。然后，可以通过物理方式了解极限周期如何通过结构之间的能量传递在其周期内的动态变化而得以维持。另外，表明背景的突然变形是由间歇结构的非线性自耦合引起的。