AI 中文总结
研究通过降低HSX主线圈6和W7-X非平面线圈5电流获得巨型岛链磁结构，用EMC3-Lite找相关构型，虽不知其对偏滤器性能是否有利，但证明该状态可获且现有机器能灵活开展边缘研究。
AI 中文摘要
我们展示了螺旋对称实验（HSX）和文德斯坦7-X（W7-X）中的磁结构，其中边缘磁结构由空间上比先前报道的构型更大的岛链主导。这些“巨型”岛链（HSX的旋转变换ι = 4/3或4/4，W7-X的ι = 5/6、5/5或5/4）通过降低HSX主线圈6和W7-X非平面线圈5（即W_7 - X中最接近上下对称横截面φ = 36°、HSX中φ = 45°的线圈）中的线圈电流获得；这似乎是巨型岛的充分（但非必要）条件。巨型岛产生相对笔直的X点支腿，将等离子体传输到面向等离子体的部件（PFCs）。在最极端情况下，岛O点离开磁力线图的区域，其余“未配对”X点的偏滤器支腿不在岛周围闭合。我们使用各向异性热扩散代码EMC3 - Lite找到对PFC热负荷有前景的“巨型岛”W7 - X构型。除了新经典输运和磁流体动力学稳定性等其他效应外，还需要进行线圈力分析，但本文未探讨。尚不清楚巨型岛是否本质上有利于偏滤器性能，但我们证明了这种远离普通岛偏滤器的状态是可获得的，原则上可通过实验研究。这也揭示了现有机器在超出其原始设计空间进行边缘研究的灵活性。
英文摘要
We present magnetic configurations in the Helically Symmetric eXperiment (HSX) and Wendelstein 7-X (W7-X), in which the edge magnetic structure is dominated by island chains which are spatially larger than the previously reported configurations. These ``giant" island chains (with rotational transform $ι=4/3$ or $4/4$ for HSX and $ι=5/6$, $5/5$ or $5/4$ for W7-X) are obtained by reducing the coil current in main coil 6 for HSX and non-planar coil 5 for W7-X (i.e. the coil nearest the up-down symmetric cross-section $ϕ=36^\circ$ for W7-X and $ϕ=45^\circ$ for HSX); this appears a sufficient (but not necessary) condition for giant islands. The giant islands create relatively straight X-point legs which transport plasma to the plasma-facing components (PFCs). In the most extreme cases, the island O-points leave the domain of the field line map and the divertor legs of the remaining ``unpaired" X-points do not close around the island. We use the anisotropic heat diffusion code EMC3-Lite to find ``giant island" W7-X configurations which are promising for PFC heat loads. Coil forces analysis (in addition to other effects such as neoclassical transport and magnetohydrodynamic stability) would also be required but are not explored here. It is not known whether giant islands are intrinsically favourable for divertor performance but we demonstrate that such regimes, which are far from the ordinary island divertor, are obtainable and can in principle be studied experimentally. This also reveals the flexibility of existing machines for edge studies beyond their original design space.
Comments23 pages, 14 figures
