Verhaegh Kevin, Harrison James, Moulton David, Lipschultz Bruce, Lonigro Nicola, Osborne Nick, Ryan Peter, Theiler Christian, Wijkamp Tijs, Brida Dominik, Cowley Cyd, Derks Gijs, Doyle Rhys, Federici Fabio, Kool Bob, Février Olivier, Hakola Antti, Henderson Stuart, Reimerdes Holger, Thornton Andrew, Vianello Nicola, Wischmeier Marco, Xiang Lingyan
United Kingdom Atomic Energy Authority, Culham, UK.
Eindhoven University of Technology, Eindhoven, The Netherlands.
Commun Phys. 2025;8(1):215. doi: 10.1038/s42005-025-02121-1. Epub 2025 May 23.
Exhausting power from the hot fusion core to the plasma-facing components is one fusion energy's biggest challenges. The MAST Upgrade tokamak uniquely integrates strong containment of neutrals within the exhaust area (divertor) with extreme divertor shaping capability. By systematically altering the divertor shape, this study shows the strongest evidence to date to our knowledge that long-legged divertors with a high magnetic field gradient (total flux expansion) deliver key power exhaust benefits without adversely impacting the hot fusion core. These benefits are already achieved with relatively modest geometry adjustments that are more feasible to integrate in reactor designs. Benefits include reduced target heat loads and improved access to, and stability of, a neutral gas buffer that 'shields' the target and enhances power exhaust (detachment). Analysis and model comparisons shows these benefits are obtained by combining multiple shaping aspects: long-legged divertors have expanded plasma-neutral interaction volume that drive reductions in particle and power loads, while total flux expansion enhances detachment access and stability. Containing the neutrals in the exhaust area with physical structures further augments these shaping benefits. These results demonstrate strategic variation in the divertor geometry and magnetic topology is a potential solution to one of fusion's power exhaust challenge.
将热核聚变堆芯的能量排放到面向等离子体的部件上，是聚变能源面临的最大挑战之一。MAST升级托卡马克装置独特地将排气区域（偏滤器）内对中性粒子的强约束与极强的偏滤器形状控制能力结合在一起。通过系统地改变偏滤器形状，本研究提供了据我们所知迄今为止最有力的证据，即具有高磁场梯度（总通量扩展）的长腿偏滤器能带来关键的能量排放优势，同时不会对热核聚变堆芯产生不利影响。这些优势已经通过相对适度的几何形状调整得以实现，而这种调整在反应堆设计中更容易整合。优势包括降低靶材热负荷，改善对中性气体缓冲层的利用以及提高其稳定性，该缓冲层可“屏蔽”靶材并增强能量排放（脱靶）。分析和模型比较表明，这些优势是通过多种形状控制因素的结合而获得的：长腿偏滤器扩大了等离子体与中性粒子的相互作用体积，从而降低了粒子和能量负荷，而总通量扩展则增强了脱靶的可达性和稳定性。利用物理结构在排气区域约束中性粒子，进一步增强了这些形状控制的优势。这些结果表明，偏滤器几何形状和磁拓扑结构的策略性变化是解决聚变能量排放挑战的一个潜在方案。
