The design of turbulence optimized stellarators has so far relied on three-dimensional equilibrium codes such as VMEC in order to find the minimum of a given objective function. In this work, we propose a complimentary approach based on the near-axis expansion to compute the geometry parameters of neoclassicaly optimized stellarators used in turbulence studies. As shown here, the near-axis expansion can be a reasonable approximation of the geometric parameters relevant for turbulence and stability simulations of the core of existing optimized stellarator designs. In particular, we examine the geometry coefficients that appear in the gyrokinetic equation, the drift-reduced fluid equations and the ideal ballooning equation. This approach may allow for the development of new stellarator optimization techniques significantly faster than conventional methods.

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近轴磁场在仿星器湍流模拟中的应用

迄今为止，湍流优化仿星器的设计依赖于 3D 平衡代码，例如 VMEC，以便找到给定目标函数的最小值。在这项工作中，我们提出了一种基于近轴扩展的补充方法来计算湍流研究中使用的新古典优化仿星器的几何参数。如此处所示，近轴膨胀可以是与现有优化仿星器设计核心的湍流和稳定性模拟相关的几何参数的合理近似值。特别是，我们检查了出现在陀螺动力学方程、减少漂移的流体方程和理想气球方程中的几何系数。