Extension of ELM suppression window using n=4 RMPs in EAST
P. Xie, Y. Sun, Q. Ma, S. Gu, Y. Q. Liu, M. Jia, A. Loarte, X. Wu, Y. Chang, T. Jia, T. Zhang, Z. Zhou, Q. Zang, B. Lyu, S. Fu, H. Sheng, C. Ye, H. Yang, H. H. … 展开作者
P. Xie, Y. Sun, Q. Ma, S. Gu, Y. Q. Liu, M. Jia, A. Loarte, X. Wu, Y. Chang, T. Jia, T. Zhang, Z. Zhou, Q. Zang, B. Lyu, S. Fu, H. Sheng, C. Ye, H. Yang, H. H. Wang, EAST Contributors
The q95 window for Type-I Edge Localized Modes (ELMs) suppression using n=4 even parity Resonant Magnetic Perturbations (RMPs) has been significantly expanded to a range from 3.9 to 4.8, which is demonstrated to be reliable and repeatable in EAST over the last two years. This window is significantly wider than the previous one, which is around q95=3.7pm0.1, and is achieved using n=4 odd parity RMPs. Here, n represents the toroidal mode number of the applied RMPs and q95 is the safety factor at the 95% normalized poloidal magnetic flux. During ELM suppression, there is only a slight drop in the stored energy (<=10%). The comparison of pedestal density profiles suggests that ELM suppression is achieved when the pedestal gradient is kept lower than a threshold. This wide q95 window for ELM suppression is consistent with the prediction made by MARS-F modeling prior to the experiment, in which it is located at one of the resonant q95 windows for plasma response. The Chirikov parameter taking into account plasma response near the pedestal top, which measures the plasma edge stochasticity, significantly increases when q95 exceeds 4, mainly due to denser neighboring rational surfaces. Modeling of plasma response by the MARS-F code shows a strong coupling between resonant and non-resonant components across the pedestal region, which is characteristic of the kink-peeling like response observed during RMP-ELM suppression in previous studies on EAST. These promising results show the reliability of ELM suppression using the n=4 RMPs and expand the physical understanding on ELM suppression mechanism.
Nitrogen-induced ELM suppression and confinement improvement in the EAST tokamak with a full metal wall
School of the Gifted Young, University of Science and Technology of China（中国科学技术大学少年班）；Institute of Plasma Physics, Chinese Academy of Sciences（中国科学院等离子体物理研究所）；School of Nuclear Science and Technology, University of Science and Technology of China（中国科学技术大学核科学与技术学院）；Southwestern Institute of Physics（西南物理研究所）
Nuclear Fusion Knowledge Graph Guided Edge-Localized Mode Recognition on EAST
School of Computer Science and Technology, Anhui University（安徽大学计算机科学与技术学院）；Department of Computer Science and Technology, Tsinghua University（清华大学计算机科学与技术系）；Institute of Plasma Physics, Chinese Academy of Sciences（中国科学院等离子体物理研究所）
