The first implementation of active detachment feedback control in EAST PCS

EAST achieved 101.2 seconds H-mode discharge with total power injection up to 3MW in 2017. Consequently to the enhanced auxiliary heating power, the active divertor heat flux control is urgently needed in EAST. In 2018, the active divertor detachment feedback control was implemented successfully in EAST plasma control system (PCS) with divertor Langmuir probe measurements for evaluating the divertor particle flux. The control algo- rithm controlled the degree of detachment effectively during the 2018 EAST experiments through either D2 fueling in the low field side using SMBI or impurity seeding from the divertor volume in H-mode plasmas, without significant degradation of the core-plasma performance, i.e., exhibiting good core-edge-divertor in- tegration. The algorithm implementation in PCS and experimental results will be reported in this paper. Further efforts will be made to extend active feedback control towards long-pulse H-mode detachment maintenance in the near future, which will benefit the high power, H-mode operation for ITER.

EAST于2017年实现了总注入功率达3兆瓦的101.2秒高约束模（H-mode）放电。随着辅助加热功率的提升，EAST亟需开展主动偏滤器热流控制相关研究。2018年，主动偏滤器脱靶反馈控制在EAST等离子体控制系统（PCS）中成功实现，该系统通过偏滤器朗缪尔探针测量来评估偏滤器粒子流。该控制算法可通过两种途径有效调控2018年EAST实验中的脱靶程度：一是利用超声分子束注入（SMBI）在低场侧进行氘气（D₂）加料，二是在高约束模等离子体中向偏滤器腔室注入杂质；且该方案未造成芯部等离子体性能的显著退化，实现了优良的芯部-边缘-偏滤器一体化运行。本文将报道该算法在PCS中的实现细节与实验结果。未来我们将进一步拓展主动反馈控制技术，以实现长脉冲高约束模脱靶维持，这将为国际热核聚变实验堆（ITER）的高功率高约束模运行提供有力支撑。