The first continuum gyrokinetic calculations of electrostatic ion scale turbulence are presented for the case of a diverted tokamak geometry. The simulation model solves the long-wavelength limit of the full-F gyrokinetic equation for ion species coupled to the quasi-neutrality equation for electrostatic potential variations, where a fluid model is used for an electron response. In order to facilitate simulations of highly-anisotropic microturbulence in the presence of strong magnetic shear and a magnetic X-point, a numerical algorithm utilizing a locally field-aligned multiblock coordinate system has been developed and implemented in the 5D finite-volume code COGENT. In this approach, the toroidal direction is divided into blocks, such that within each block, the cells are field-aligned and a non-matching grid interface is allowed at block boundaries. The toroidal angle corresponds to the “coarse” field-aligned coordinate, whereas the poloidal cross section, comprised of the radial and poloidal directions, is finely gridded to resolve short-scale perpendicular turbulence structures and to support accurate re-mapping (interpolation) at block boundaries. The 5D simulations explore cross-separatrix ion scale turbulence in the presence of a self-consistent radial electric field and address the effects of magnetic-shear stabilization in the X-point region.

中文翻译：

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单空几何中边缘等离子体的连续陀螺动力学模拟

针对托卡马克几何形状的变化，首次提出了静电离子尺度湍流的连续体动力学计算。该仿真模型解决了离子物种的全F陀螺动力学方程与静电势变化的拟中性方程耦合的长波极限，其中流体模型用于电子响应。为了在强磁切变和磁X点存在的情况下促进高各向异性微湍流的模拟，已经开发了利用局部场对准的多块坐标系的数值算法，并在5D有限体积代码COGENT中实现。在这种方法中，将环形方向划分为多个块，以便在每个块内，这些单元是场对齐的，并且在块边界处允许使用不匹配的网格接口。环形角对应于“粗”场对准的坐标，而由径向和极向组成的极向横截面被精细地网格化，以解析短尺度垂直湍流结构并支持精确的重新映射（插值）。块边界。5D模拟在存在自洽的径向电场的情况下探索了横隔线离子尺度的湍流，并解决了X点区域中磁剪切稳定的影响。精确地网格化以解决短尺度垂直湍流结构并支持在块边界处进行精确的重新映射（插值）。5D模拟在存在自洽的径向电场的情况下探索了横隔线离子尺度的湍流，并解决了X点区域中磁剪切稳定的影响。精确地网格化以解决短尺度垂直湍流结构并支持在块边界处进行精确的重新映射（插值）。5D模拟在存在自洽的径向电场的情况下探索了横隔线离子尺度的湍流，并解决了X点区域中磁剪切稳定的影响。