Edge localized mode (ELM) mitigation accompanied by density pump-out has been achieved during the application of resonant magnetic perturbation (RMP) with a toroidal mode number of n = 4 on EAST recently. The mean ELM frequency increases by a factor of 2.7 from 86 to 235 Hz with a decreased reduction in ELM loss. The evolution of pedestal electron density measured by a profile reflectometer before and after turning on the RMP current is presented. Both the pedestal density and density gradient show a decrease with application of RMP. The density fluctuation in the pedestal region has been measured by an O-mode fluctuation reflectometer. The broadband density fluctuation with a frequency range of 20–115 kHz is enhanced at the later period of the inter-ELM phase during ELM mitigation. This phenomenon is also observed for magnetic fluctuation measured by magnetic probes mounted in the vacuum vessel. A further study shows that the enhanced broadband fluctuations lead to a decrease in the growth rate of the pedestal density and an increase in divert or particle flux. This result implies that these enhanced broadband fluctuations could lead to an enhancement of outward particle transport. The possible roles of the enhanced fluctuations observed in ELM mitigation are also discussed.

中文翻译：

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在 EAST 上用共振磁扰动 ELM 减缓过程中增强基座湍流的观察

最近在 EAST 上应用环形模式数为 n = 4 的谐振磁扰 (RMP) 期间，已经实现了伴随密度泵出的边缘局部模式 (ELM) 缓解。平均 ELM 频率从 86 Hz 增加到 235 Hz，增加了 2.7 倍，而 ELM 损失的减少减少。介绍了在打开 RMP 电流之前和之后由轮廓反射计测量的基座电子密度的演变。基座密度和密度梯度都显示出随着 RMP 的应用而降低。基座区域的密度波动已由 O 型波动反射计测量。在 ELM 缓解期间的 ELM 间阶段后期，频率范围为 20-115 kHz 的宽带密度波动得到增强。通过安装在真空容器中的磁探针测量的磁波动也观察到这种现象。进一步的研究表明，增强的宽带波动导致基座密度增长率的降低和转向或粒子通量的增加。这一结果意味着这些增强的宽带波动可能导致向外粒子传输的增强。还讨论了在 ELM 缓解中观察到的增强波动的可能作用。