AI 中文总结
本工作扩展GBS代码以支持反场箍缩构型的边界湍流模拟，应用于RFX-mod等离子体模拟发现其边缘流体湍流建模因短平行连接长度存在局限，捕获电子模是主导微观不稳定性。
AI 中文摘要
磁约束聚变装置中的湍流输运决定了整体等离子体约束特性，并调控第一壁处的等离子体-材料相互作用。在等离子体边界，湍流通常通过三维双流体通量驱动湍流模拟进行研究。本工作扩展了GBS边界湍流代码，使其能够开展反场箍缩构型下的湍流模拟，涵盖反转面和任意程度的磁混沌。代码中实现的微分算子经过修改，以避免大纵横比和弱极向磁场的近似；同时实现了三维泊松方程和安培方程求解器，支持部分或完全破坏的磁通量面条件下的湍流模拟。将该修改后的GBS代码应用于模拟RFX-mod反场箍缩等离子体边界的湍流，发现反转面处的湍流涡旋特性与托卡马克边界湍流模拟中典型的特性相似。尽管与实验测量结果吻合良好，但这些模拟揭示了反场箍缩等离子体边缘区域基于流体的湍流建模存在显著局限，该局限源于固有的短平行连接长度，线性 gyrokinetic 分析也支持这一结论，其识别出该区域中捕获电子模是主导的微观不稳定性。
英文摘要
Turbulent transport in magnetic confinement fusion devices governs the overall plasma confinement properties and regulates the plasma-material interaction at the first wall. In the plasma boundary, turbulence is typically investigated through three-dimensional two-fluid flux-driven turbulence simulations. In this work, the GBS boundary turbulence code is extended to enable turbulence simulations in reversed field pinch configurations, encompassing the reversal surface and an arbitrary level of magnetic chaos. The differential operators implemented in the code are modified to avoid the approximations of large-aspect ratio and weak poloidal magnetic field. Three-dimensional Poisson and Ampere solvers are implemented to allow for turbulence simulations in conditions of partially or fully disrupted magnetic flux surfaces. This modified version of the GBS code is then applied to simulate turbulence in the boundary of RFX-mod reversed field pinch plasmas. Turbulent eddies across the reversal surface show properties similar to those typically found in tokamak boundary turbulence simulations. Despite the good agreement found with experimental measurements, these simulations reveal a significant limitation of the fluid-based turbulence modeling of the edge region in reversed field pinch plasmas, which arises from the intrinsically short parallel connection length. This conclusion is also supported by a linear gyrokinetic analysis that identifies trapped electron modes as the dominant microinstability in this region.
