发表机构
Zhejiang University; University of Wisconsin, Madison; Shanghai Jiao Tong University; Galaxy Energy LLC; Princeton University（浙江大学; 威斯康星大学麦迪逊分校; 上海交通大学; 银河能源有限责任公司; 普林斯顿大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出准对称仿星器的等效托卡马克理论，用三个几何量表征其湍流输运，并通过回旋动理学模拟验证了定量一致性。
AI 中文摘要
众所周知，准对称（QS）仿星器在新古典输运性质方面与托卡马克同构，相应的输运系数可以像托卡马克一样计算。然而，关于QS仿星器的湍流输运性质，例如离子温度梯度（ITG）模的输运系数，人们知之甚少。本文基于局部回旋动理学公式和近轴展开理论，提出了QS仿星器的“等效托卡马克”的系统理论。结果表明，在小半径的零阶近似下，等效托卡马克可以具有圆形磁通面，并可由三个几何量表征：纵横比、旋转变换和磁剪切。然而，要达到一阶精度，并非所有QS仿星器都有等效托卡马克，但在某些情况下，可以找到全局或局部平衡的良好近似。对选定的QS构型进行了ITG输运的局部和全局回旋动理学模拟，发现仿星器与其等效托卡马克在湍流输运水平上定量一致。
英文摘要
It is well known that quasi-symmetric (QS) stellarators are isomorphic to tokamaks in terms of their neoclassical-transport properties, and the corresponding transport coefficients can be calculated in the same manner as in tokamaks. However, less is known regarding the turbulent-transport properties of QS stellarators, e.g. the transport coefficients from the ion-temperature-gradient (ITG) mode. In this work, a systematic theory of the ``equivalent tokamaks'' for QS stellarators is presented based on the local gyrokinetic formulation and the near-axis expansion theory. It is shown that to zeroth order in the minor radius, the equivalent tokamaks can be chosen to have circular flux surfaces and can be characterized by three geometric quantities: the aspect ratio, the rotational transform, and the magnetic shear. To achieve first-order accuracy, however, not all QS stellarators have equivalent tokamaks, but good approximations can be found for some cases either as global or local equilibria. Local and global gyrokinetic simulations of ITG transport are performed for a selection of QS configurations, and quantitative agreement in the turbulent transport levels is found between the stellarators and their equivalent tokamaks.
