University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
FOM Institute DIFFER, 3430 BE Nieuwegein, The Netherlands.
Phys Rev Lett. 2016 Feb 26;116(8):085001. doi: 10.1103/PhysRevLett.116.085001. Epub 2016 Feb 23.
Owing to complex geometry, gyrokinetic simulations in stellarator geometry produce large numbers of subdominant unstable and stable, near-orthogonal eigenmodes. Here, results based on the full eigenmode spectrum in stellarator geometry are presented for the first time. In the nonlinear state of a low-magnetic-shear ion-temperature-gradient-driven case, a multitude of these modes are active and imprint the system. Turbulent frequency spectra are broadband as a consequence, in addition to a nonlinear, narrow signature at electron frequencies. It is shown that successful quasilinear, mixing-length transport modeling is possible in stellarators, where it is essential to account for all subdominant unstable modes.
由于几何形状复杂，仿星器几何中的回旋动理学模拟产生了大量的次主导不稳定和稳定的近正交本征模式。这里首次呈现了基于仿星器几何全本征模谱的结果。在低磁剪切离子温度梯度驱动情形的非线性状态下，大量的这些模式是活跃的，并影响系统。结果是，除了非线性的、在电子频率处的窄特征之外，湍流频谱是宽带的。结果表明，在必须考虑所有次主导不稳定模式的情况下，准线性混合长度输运模型在仿星器中是可行的。
