University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Phys Rev Lett. 2011 Mar 18;106(11):115003. doi: 10.1103/PhysRevLett.106.115003. Epub 2011 Mar 16.
In the context of toroidal gyrokinetic simulations, it is shown that a hierarchy of damped modes is excited in the nonlinear turbulent state. These modes exist at the same spatial scales as the unstable eigenmodes that drive the turbulence. The larger amplitude subdominant modes are weakly damped and exhibit smooth, large-scale structure in velocity space and in the direction parallel to the magnetic field. Modes with increasingly fine-scale structure are excited to decreasing amplitudes. In aggregate, damped modes define a potent energy sink. This leads to an overlap of the spatial scales of energy injection and peak dissipation, a feature that is in contrast with more traditional turbulent systems.
在环形 gyrokinetic 模拟的背景下，研究表明在非线性湍流状态下会激发一系列阻尼模式。这些模式与驱动湍流的不稳定本征模式具有相同的空间尺度。幅度较大的次主导模式阻尼较弱，在速度空间和与磁场平行的方向上呈现出平滑的大尺度结构。结构越来越精细的模式以越来越小的幅度被激发。总的来说，阻尼模式定义了一个有效的能量汇。这导致了能量注入和峰值耗散的空间尺度的重叠，这与更传统的湍流系统形成对比。
