发表机构
Institute of Advanced Energy, Kyoto University（京都大学先进能源研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究铁素体钢对Heliotron J装置低剪切磁构型的影响，用点偶极磁化模型评估，发现其对安装位置敏感，源于场与微扰耦合。还表明适当布置无源磁偶极可降螺旋纹波、保磁阱深度并诱发边界微扰。
AI 中文摘要
利用点偶极磁化模型，研究了铁素体钢对Heliotron J装置低剪切仿星器/螺旋磁体磁构型的影响。通过对Heliotron J真空容器内多个位置假设的铁素体钢板进行数值评估，结果表明旋转变换和磁岛宽度的变化对安装位置敏感。这种敏感性源于背景非轴对称场与铁氧体微扰之间的耦合，而非仅由微扰幅度决定。放置在直线段外侧的铁素体钢板会使磁拓扑产生最显著变化，且对违反\(M = 4\)环形周期性最为敏感。此外，研究表明适当布置无源磁偶极可在保持Heliotron J真空磁阱深度的同时降低有效螺旋纹波，并能在接近铁氧体饱和阈值的低场实验中诱发仿星器不对称边界微扰。
英文摘要
The influence of ferritic steel on low-shear stellarator/heliotron magnetic configurations is investigated for the Heliotron J device using a point dipole magnetisation model. By numerically evaluating ferritic steel plates assumed at several locations inside the Heliotron J vacuum vessel, the changes in the rotational transform and magnetic island width are shown to be sensitive to the installation location. This location sensitivity arises from the toroidal variation of poloidal mode coupling between the background nonaxisymmetric field and ferritic-steel perturbation, rather than being determined solely by the perturbation amplitude. The resulting mode coupling can enhance the resonant vacuum magnetic perturbation at specific locations. Ferritic steel plates placed on the outer side of a straight section produce the most significant changes in the magnetic topology and exhibit the highest sensitivity to violations of the $M=4$ toroidal periodicity. Additionally, we show that appropriate arrangements of passive magnetic dipoles can reduce the effective helical ripple while preserving the vacuum magnetic well depth in Heliotron J, and can induce a stellarator-asymmetric boundary perturbation in low-field experiments.
Comments21 pages, 14 figures
