利用偏滤器气体注入对KSTAR中ELM频率的实时反馈控制及其对钨诱导辐射和等离子体性能的影响
Real-time feedback control of ELM frequency using divertor gas puffing and its effects on tungsten-induced radiation and plasma performance in KSTAR
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中文总结 AI 辅助
本研究在KSTAR装置中采用PI反馈控制器，以D₂偏滤器气体注入为执行器实时控制ELM频率，实现了对芯部钨的排出，同时避免了等离子体性能的显著下降，凸显了实时优化的必要性。
中文摘要 AI 辅助
在KSTAR装置的钨偏滤器条件下，研究人员采用比例积分（PI）反馈控制器，以D₂偏滤器气体注入作为执行器，成功实现了对边缘局域模（ELM）频率（f_ELM）的实时控制。该控制器精准跟踪了两步目标：将f_ELM提升30 Hz并持续4秒，随后降低30 Hz并持续3秒，对应的平均绝对百分比误差约为13%，中位数绝对百分比误差约为12%。与参考放电相比，主动控制的放电并未出现体积积分芯部辐射的显著下降，这证实过量气体使用仅会降低整体等离子体性能。而与未使用偏滤器气体注入时观察到的芯部辐射指数增长相比，这些结果凸显了实时优化的关键必要性：必须主动管理偏滤器气体指令，以维持足够的f_ELM，从而将钨从芯部排出，同时最大化全局等离子体性能。
英文摘要
The edge-localized mode (ELM) frequency ($f_{\mathrm{ELM}}$) was successfully controlled in real time on KSTAR using a proportional-integral (PI) feedback controller, employing a $\mathrm{D}_2$ divertor gas puff as the actuator under tungsten lower-divertor conditions. The controller accurately tracked a two-step target---a 30 Hz increase in $f_{\mathrm{ELM}}$ for 4 s, followed by a 30 Hz decrease for 3 s---yielding mean and median absolute percentage errors of approximately 13% and 12%, respectively. Compared to a reference discharge, the actively controlled shot did not exhibit a significant drop in volume-integrated core radiation, confirming that excessive gas use merely degrades overall plasma performance. However, when contrasted with the exponential increase in core radiation observed in the absence of divertor gas puffing, these results underscore the critical need for real-time optimization. Specifically, divertor gas commands must be actively managed to maintain an $f_{\mathrm{ELM}}$ sufficient for flushing tungsten from the core while maximizing global plasma performance.
