Gyrokinetic turbulence: between idealized estimates and a detailed analysis of nonlinear energy transfers
Gyrokinetic turbulence: between idealized estimates and a detailed analysis of nonlinear energy transfers
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回旋湍流：理想化估计与非线性能量传递的详细分析之间
DOI：
10.1088/1367-2630/aa6998
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发表时间：
2016
影响因子：
3.3
通讯作者：
D. Told
中科院分区：
文献类型：
--
作者：
B. Teaca;F. Jenko;D. Told
利用大分辨率的数值模拟的回旋运动（GK）湍流，跨越一个区间范围从年底的流体尺度的电子gyroradius，我们研究的能量转移在垂直方向上的质子-电子等离子体在板状平衡磁几何形状。这里所采用的等离子体参数是有关动力学阿尔文波湍流太阳风条件。此外，我们使用一个理想化的测试表示的两个尺度之间的能量转移，以帮助我们理解的诊断适用于无限惯性范围内的非线性级联。对于GK湍流，详细分析了能量交换尺度分离的非线性能量传递。从研究的能量级联和规模局部性问题，我们表明，一般的非局部性质的GK湍流，通过局部性函数捕获，包含一个子集的相互作用，被认为是本地的，规模不变（即一个符号的渐近局部性），并拥有一个局部指数，可以直接从测量的能量级联。这是第一次，GK湍流具有渐近局部分量，即使整体局部的相互作用是非局部的。这里提出的结果和它们的影响进行了讨论，从以前的研究结果在文献中报道的角度和GK湍流的普遍性的想法。
Using large resolution numerical simulations of gyrokinetic (GK) turbulence, spanning an interval ranging from the end of the fluid scales to the electron gyroradius, we study the energy transfers in the perpendicular direction for a proton–electron plasma in a slab equilibrium magnetic geometry. The plasma parameters employed here are relevant to kinetic Alfvén wave turbulence in solar wind conditions. In addition, we use an idealized test representation for the energy transfers between two scales, to aid our understanding of the diagnostics applicable to the nonlinear cascade in an infinite inertial range. For GK turbulence, a detailed analysis of nonlinear energy transfers that account for the separation of energy exchanging scales is performed. Starting from the study of the energy cascade and the scale locality problem, we show that the general nonlocal nature of GK turbulence, captured via locality functions, contains a subset of interactions that are deemed local, are scale invariant (i.e. a sign of asymptotic locality) and possess a locality exponent that can be recovered directly from measurements on the energy cascade. It is the first time that GK turbulence is shown to possess an asymptotic local component, even if the overall locality of interactions is nonlocal. The results presented here and their implications are discussed from the perspective of previous findings reported in the literature and the idea of universality of GK turbulence.