EAST上锂球注入缓解I型边界局域模的行为机制研究

With the increment of heating power and the stepwise replacement of the metal wall on EAST, how to eliminate the high transient heat load on divertor plate caused by the type-I edge localized modes (ELMs) has become one urgent problem for the steady state operation of EAST and future fusion devices. As a new technology of ELMs control, lithium granules injection has successfully triggered ELMs in EAST. However, the effects of lithium granules injection on type-I ELMs mitigation and physical mechanism is still unclear. In the low pedestal collisionality region, this project will carry out the experiment of lithium granule injection to mitigate type I ELMs on EAST. We will research the effect of type-I ELMs mitigation and its effect on plasma performance. We will analyze the influence of the first wall materials and the injection parameters on the type-I ELMs mitigation by lithium granule injection. The physical mechanism of ELM mitigation by lithium granule injection will be explored on EAST. This project will develop a reliable, innovative, low-cost ELM mitigation technology for EAST and future fusion device to avoid high transient heat load on divertor plate. The research output of this project could provide useful reference on ELM mitigation by fuel and other low Z impurities pellet injection.

随着EAST加热功率的提高和金属壁的不断升级，如何可靠的缓解I型边界局域模（ELM）对靶板的瞬态热冲击成为EAST和未来核聚变装置稳态运行的亟待解决的问题。锂球注入作为新型的ELM控制手段，在EAST上已经成功触发ELM，但是锂球注入对I型ELM缓解的效果及物理机制尚不清楚。本项目依托EAST托卡马克实验平台，在低边界碰撞率参数区，开展锂球注入缓解I型ELM物理实验，研究锂球注入对I型ELM缓解效果及其对等离子体约束性能的影响，分析第一壁材料、锂球注入参数对锂球注入缓解I型ELM效果的影响，探索锂球注入缓解ELM的物理机制。本申请项目将为EAST和未来聚变装置发展一种可靠的、创新的、低成本的ELM缓解手段，对于EAST及未来聚变堆装置控制高能瞬态热负荷有重要意义，也为燃料弹丸和其它低Z杂质弹丸注入控制ELM提供有效参考。

对于未来聚变装置，缓解第一类边界局域模（ELM）对第一壁瞬间热沉积是未来聚变堆必须亟待解决的问题。本项目通过在EAST装置上开展不同参数锂弹丸注入实验，研究锂弹丸注入第一类ELM缓解效果及其对等离子体行为的影响，成功构建了锂弹丸中性气体屏蔽消融数值计算模型并弹丸消融诊断，能够确定不同尺寸锂弹丸在边界等离子体中的沉积位置；研制一种新型、便宜的锂弹丸制备技术并完成锂弹丸注入系统优化和关键参数标定，满足锂弹丸注入控制ELM的基本硬件需求；在EAST上成功开展不同参数的锂弹丸注入实验，证明钨壁条件下，锂弹丸注入成功触发ELM，首次实现锂弹丸注入完全控制ELM频率，高频小尺寸弹丸注入情况下发现弹丸注入能够增加ELM频率，降低ELM尺寸，钨壁条件下首次发现锂弹丸注入触发ELM存在弹丸尺寸阈值。这些实验结果为进一步开展钨壁条件下锂弹丸注入缓解大型ELM做好良好铺垫，为EAST发现钨壁条件下ELM控制技术做好基础，并且为ITER采用燃料弹丸注入控制ELM提供良好数据参考。