Article
Physics, Fluids & Plasmas
Rong Wang, Zhongshi Yang, Kedong Li, Guosheng Xu, Guozhang Jia, Guojian Niu, Feifei Nian, Tao He, Lingyi Meng, Xin Lin, Guang-Nan Luo, Liang Wang
Summary: By using Ne seeding, EAST has achieved plasma detachment, with a decrease in electron temperature leading to a significant drop in poloidal saturation ion current. Simulation results show that this is mainly driven by the rise of momentum loss and upstream pressure loss.
PHYSICS OF PLASMAS
(2022)
Article
Nuclear Science & Technology
K. Wu, Q. P. Yuan, D. Eldon, K. D. Li, Y. M. Duan, L. Y. Meng, L. Wang, H. Q. Wang, J. J. Huang, L. Zhang, Z. P. Luo, X. J. Liu, B. Cao, J. B. Liu, F. Ding, G. S. Xu, J. S. Hu, B. J. Xiao, G. Calabro, P. Innocente
Summary: EAST implements double feedback control experiments by using two control systems simultaneously to explore a new detachment control method. The control method involves using two PID controllers and two gas puffing valves to inject impurity gases, increasing radiated power and reducing electron temperature. The experiments showed a significant reduction in divertor heat flux during the control phase. However, the injection of argon gas resulted in an unfavorable increase in core radiated power, pausing the radiative feedback control for a long time and degrading control precision. Future work will focus on mitigating this issue and optimizing the control system.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Physics, Fluids & Plasmas
Jianbin Liu, Lingyi Meng, Houyang Guo, Kedong Li, Jichan Xu, Huiqian Wang, Guosheng Xu, Fang Ding, Ling Zhang, Yanmin Duan, Bin Zhang, Lin Yu, Ping Wang, Ang Li, Donggui Wu, Rui Ding, Liang Wang
Summary: Detachment in helium discharges has been achieved by increasing plasma density, which is different from that in deuterium discharges. The detachment threshold in helium plasma is higher than that in deuterium plasma and increases with heating power.
PLASMA SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
G. S. Xu, L. Wang, D. M. Yao, G. Z. Jia, C. F. Sang, X. J. Liu, Y. P. Chen, H. Si, Z. S. Yang, H. Y. Guo, H. L. Du, Z. P. Luo, H. Li, Z. B. Zhou, L. Cao, H. C. Xu, T. J. Xu, Z. L. Wang, P. F. Zi, L. Li, L. Han, J. C. Xu, J. B. Liu, K. D. Li, B. Cao, Y. W. Yu, F. Ding, R. Ding, N. Yan, L. Y. Meng, Y. Q. Tao, H. Q. Wang, Y. Zhang, L. M. Shao, X. D. Zhang, S. Z. Zhu, B. N. Wan
Summary: A new lower tungsten divertor has been developed and installed in the EAST tokamak to increase power handling capability, aiming at achieving long-pulse H-mode operations. The 'corner slot' divertor concept allows for stable detachment operation in a full metal wall environment.
Article
Nuclear Science & Technology
D. Eldon, H. Q. Wang, L. Wang, J. Barr, S. Ding, A. Garofalo, X. Z. Gong, H. Y. Guo, A. E. Jarvinen, K. D. Li, J. McClenaghan, A. G. McLean, C. M. Samuell, J. G. Watkins, D. Weisberg, Q. P. Yuan
Summary: Experiments at DIII-D and EAST have shown the importance of controlling divertor detachment and detachment level within ITER requirements. Different methods, such as nitrogen, neon, and argon seeding, have been tested with varying degrees of success in maintaining core performance while achieving detachment. The presence of an Internal Transport Barrier (ITB) seems crucial for retaining core performance during detachment.
NUCLEAR MATERIALS AND ENERGY
(2021)
Article
Nuclear Science & Technology
R. Maurizio, A. W. Leonard, A. G. Mclean, M. W. Shafer, P. C. Stangeby, D. Thomas, J. H. Yu
Summary: A staged divertor program is being discussed to advance DIII-D research on core-edge integration. The role of slot depth in achieving highly dissipative divertor conditions in both magnetic field directions is studied. Increasing the slot depth reduces the upstream separatrix electron density needed to detach and improves neutral leakage reduction, leading to increased divertor radiation and lower detachment density threshold.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Physics, Multidisciplinary
N. . Ding, Q. Q. Yang, L. Wang, G. S. Xu, L. Y. Meng, K. D. Li, X. Lin, X. Liu, K. X. Ye, Q. Zhang, F. Ding, G. F. Ding, Y. B. Wang
Summary: In the experiments, the reattachment of the detached divertor plasma caused by the transient heat flux induced by ELMs, known as ELM burn-through, has been studied. The study evaluates the affected area of small ELMs on the divertor target and finds that the radial extension of small ELMs is limited. It also reveals that the occurrence of small ELM burn-through is highly correlated with the degree of divertor detachment and ELM frequency. The burn-through is triggered by the accumulated particles and energy of multiple small ELMs, not by a single small ELM.
Article
Physics, Fluids & Plasmas
L. Y. Meng, L. Wang, H. Q. Wang, G. Z. Deng, H. Si, K. D. Li, G. S. Xu, Q. P. Yuan, H. Y. Guo, D. Eldon, A. M. Garofalo, A. W. Leonard, A. Hyatt, D. Humphreys, X. Z. Gong, J. B. Liu, J. C. Xu, R. R. Liang, F. B. Zhong, X. Lin, Y. M. Duan, Q. Zang, L. Zhang, F. Ding, Z. S. Yang, B. Zhang, T. Zhang
Summary: Active impurity seeding is an effective method to reduce excessively high divertor heat flux. In the EAST experimental campaign, a mixture of neon and deuterium was used to achieve partial detachment and core-edge-divertor integration. Seeding impurities in the SOL downstream is more beneficial for reducing divertor electron temperature and heat flux. Seeding close to the strike point enhances neon ionization and energy radiation.
Article
Physics, Fluids & Plasmas
S. S. Henderson, M. Bernert, D. Brida, M. Cavedon, P. David, R. Dux, O. Fevrier, A. Jarvinen, A. Kallenbach, M. Komm, R. McDermott, M. O'Mullane
Summary: Using newly developed spectroscopic models, the concentration of Ne and Ar in the divertor was measured. The experimental detachment threshold on ASDEX Upgrade with Ar-only and mixtures of Ar+N or Ne+N matches an analytical equation. However, the efficiency of Ar and Ne radiation in the scrape-off layer is different from the model predictions. The reattachment of partially detached and strongly detached X-point radiator scenarios has different timescales and is influenced by core energy confinement and the movement of the ionisation front.
Article
Physics, Fluids & Plasmas
Tao He, Zhongshi Yang, Liang Wang, Kedong Li, Huiqian Wang, David Eldon, Alan Hyatt, David Humphreys, Lingyi Meng, Fang Ding, Yuming Wang, Yanmin Duan, Ling Zhang, Jichan Xu, Yu Luo, Dawei Ye, Xiahua Chen, Qingquan Yang, Feifei Nian, Guojian Niu, Guosheng Xu, Guang-Nan Luo
Summary: Experiments on EAST have shown that impurity seeding from different locations can lead to partial energy detachment and reduce heat flux on the targets. The study also found that the location of injection can affect the asymmetry of particle and heat flux, with only a slight decrease in plasma confinement during detachment.
PLASMA PHYSICS AND CONTROLLED FUSION
(2021)
Article
Physics, Fluids & Plasmas
Ping Wang, Guanghai Hu, Ning Yan, Guosheng Xu, Lingyi Meng, Zhikang Lu, Lin Yu, Manni Jia, Yifeng Wang, Liang Chen, Heng Lan, Xiang Liu, Mingfu Wu, Liang Wang
Summary: The study investigates the relationship between the scrape-off layer (SOL) blob transition and divertor detachment using Lithium Beam Emission Spectroscopy systems and Langmuir probe arrays embedded in the divertor target plates on EAST. The results show that when the plasma density exceeds a certain threshold, the size and lifetime of the blobs increase while the detection rate decreases. Additionally, a weak density shoulder is observed in the near SOL region at the same density threshold. The study suggests that divertor detachment is highly correlated with blob transition.
PLASMA SCIENCE & TECHNOLOGY
(2022)
Article
Nuclear Science & Technology
M. S. Islam, J. D. Lore, S. Smolentsev, C. E. Kessel
Summary: The SOLPS-ITER code was used to analyze the SOL plasma in the fast flow Lithium (Li) divertor design for FNSF. Two divertor configurations were investigated, and it was found that a balanced geometry with baffling has acceptable operational windows, while a simplified open geometry presents challenges. The effect of Li sourcing on the plasma conditions was also studied, and it was observed that high levels of Li sourcing strongly affect the divertor and upstream plasmas.
NUCLEAR MATERIALS AND ENERGY
(2022)
Article
Physics, Fluids & Plasmas
H. Q. Wang, D. M. Thomas, A. W. Leonard, X. X. Ma, H. Y. Guo, A. L. Moser, J. G. Watkins, F. Scotti, C. Lasnier, M. E. Fenstermacher, A. G. McLean, M. W. Shafer, B. Grierson, J. Ren, T. H. Osborne
Summary: Experiments in DIII-D demonstrate that higher plasma current and heating power combined with impurity seeding facilitate divertor detachment and improve plasma performance in a closed divertor compared to an open divertor.
Article
Physics, Fluids & Plasmas
Chaofeng Sang, Qingrui Zhou, Guosheng Xu, Liang Wang, Yilin Wang, Xuele Zhao, Chen Zhang, Rui Ding, Guozhang Jia, Damao Yao, Xiaoju Liu, Hang Si, Dezhen Wang
Summary: This study focuses on the physical design and optimization of a tungsten divertor using 2D edge plasma and Monte Carlo impurity transport codes. It compares the effects of argon and neon impurity seeding on divertor performance, as well as tungsten target erosion and impurity transport. The study also demonstrates the effectiveness of an open vertical inner target in reducing in-out asymmetry.
Article
Physics, Fluids & Plasmas
Fuqiong Wang, Yunfeng Liang, Yingfeng Xu, Xuejun Zha, Fangchuan Zhong, Songtao Mao, Yanmin Duan, Liqun Hu
Summary: To better understand divertor detachment and asymmetry in EAST, drift modeling of neon impurity seeded plasmas in favorable/unfavorable BT has been performed. Simulation results show that in favorable BT, the onset of detachment is highly asymmetric between the inner and outer divertors, while reversing BT can decrease the magnitude of in-out asymmetry. This work sheds light on the physics reasons behind the observed divertor detachment and asymmetry in EAST.
PLASMA SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
G. Z. Deng, X. Q. Xu, N. M. Li, X. J. Liu, X. Liu, J. C. Xu, W. Feng, J. B. Liu, S. L. Gao, S. C. Liu, T. Y. Xia, L. Wang
Article
Nuclear Science & Technology
Binfu Gao, Rui Ding, Hai Xie, Long Zeng, Ling Zhang, Baoguo Wang, Changjun Li, Dahuan Zhu, Rong Yan, Junling Chen
FUSION ENGINEERING AND DESIGN
(2020)
Article
Physics, Fluids & Plasmas
Lan Yin, Cheng Yang, Xinjun Zhang, Pingwei Zheng, Haiqing Liu, Guoqiang Li, Yifeng Wang, Yingying Li, Bo Lyu, Qing Zang, Zhen Zheng, Zongzheng Men, Chengyi Song, Qianhong Huang, You Chen, Xueyu Gong
PHYSICS OF PLASMAS
(2020)
Article
Physics, Fluids & Plasmas
X. J. Liu, G. L. Xu, R. Ding, G. Z. Jia, C. F. Sang, H. Si, F. F. Nian, Z. S. Yang, G. Q. Li, V. S. Chan, G. Z. Deng, S. L. Gao, X. Gao
PHYSICS OF PLASMAS
(2020)
Article
Nanoscience & Nanotechnology
Shanlu Gao, Xiaoju Liu, Guozhong Deng, Tingfeng Ming, Guoqiang Li, Xuexi Zhang, Yuqiang Tao, Xiang Gao
Summary: The study shows that bundled charge state models can effectively describe divertor parameters of tungsten, improve code speed and save computational resources. In the low recycling regime, differences between different bundling schemes are within 15%, while in the high recycling regime, there is minimal variation due to low tungsten concentration.
Article
Nanoscience & Nanotechnology
Qiqi Shi, Tingfeng Ming, Qing Zhuang, Feifei Long, Bang Li, Shanlu Gao, Guozhong Deng, Shaocheng Liu, Yumin Wang, Xiaoju Liu, Long Zeng, Xiaolan Liu, Xiang Gao
Summary: In type I ELMy H-mode experiment, ELM filaments were captured using a high-speed vacuum ultraviolet imaging system. Singular value decomposition was performed on imaging data to analyze the structures, which were characterized by pitch angle and poloidal width. Changes in poloidal width during ELM crash were observed, with filaments aligning with field lines and poloidal velocity increasing with heating power.
Article
Physics, Fluids & Plasmas
G. Z. Deng, X. Q. Xu, X. J. Liu, J. C. Xu, L. Y. Meng, J. B. Liu, N. M. Li, L. Schmitz, S. L. Gao, Q. Q. Yang, Y. Ye, T. Y. Xia, S. C. Liu, T. F. Ming, G. S. Xu, X. D. Lin, G. Q. Li, X. Gao, L. Wang
Summary: The study investigated the effects of radial transport on outer divertor particle and power flux widths using plasmas in different operational regimes in EAST. Results showed varying lambda (js) values under different plasma operational modes, and simulations indicated that lambda (q) and lambda (js) increase with D and chi (e), with background turbulence becoming significant at higher D or chi (e) levels. Additionally, divertor geometry and plasma density were found to have significant influences on lambda (js) and the ratio of lambda (js) to lambda (q) according to simulations using SOLPS.
Article
Physics, Fluids & Plasmas
Zhuang Liu, Rui Ding, Xueqiao Xu, Nami Li, Guozhong Deng, Jizhong Sun, Dezhen Wang, Yan Feng
Summary: This study utilized the NDS module under the BOUT++ framework to simulate the transport and evolution of small dust along their trajectories, revealing the significant influence of magnetic field on dust behavior based on size and source.
PHYSICS OF PLASMAS
(2021)
Article
Physics, Fluids & Plasmas
Youjun Hu, Yingfeng Xu, Baolong Hao, Guoqiang Li, Kaiyang He, Youwen Sun, Li Li, Jinfang Wang, Juan Huang, Lei Ye, Xiaotao Xiao, Feng Wang, Chengkang Pan, Yongjian Xu
Summary: The study investigates the effects of resonant magnetic perturbations (RMPs) on tangential neutral beam heating in the EAST tokamak through numerical simulations. Different configurations of RMP coil currents are examined to minimize the deleterious effects on the neutral beam injection (NBI) heating efficiency. The study finds that RMPs can induce local accumulation of fast ions and affect the radial profile of fast ions, while the toroidal phasing of RMP has slight effects on the steady-state fast ions distribution. This research also proposes a statistical method to identify resonances between RMPs and lost fast ions, revealing non-integer fractional order resonances between RMPs and lost passing particles.
PHYSICS OF PLASMAS
(2021)
Article
Physics, Fluids & Plasmas
L. Y. Meng, L. Wang, H. Q. Wang, G. Z. Deng, H. Si, K. D. Li, G. S. Xu, Q. P. Yuan, H. Y. Guo, D. Eldon, A. M. Garofalo, A. W. Leonard, A. Hyatt, D. Humphreys, X. Z. Gong, J. B. Liu, J. C. Xu, R. R. Liang, F. B. Zhong, X. Lin, Y. M. Duan, Q. Zang, L. Zhang, F. Ding, Z. S. Yang, B. Zhang, T. Zhang
Summary: Active impurity seeding is an effective method to reduce excessively high divertor heat flux. In the EAST experimental campaign, a mixture of neon and deuterium was used to achieve partial detachment and core-edge-divertor integration. Seeding impurities in the SOL downstream is more beneficial for reducing divertor electron temperature and heat flux. Seeding close to the strike point enhances neon ionization and energy radiation.
Article
Nanoscience & Nanotechnology
Xuexi Zhang, Guoqiang Li, Muquan Wu, Tengfei Tang, Xiaoju Liu, Shanlu Gao, Xiaohe Wu, Xiang Gao
Summary: This study simulated the operation modes with negative central shear and large-radius ITBs in EAST and identified important factors for achieving such scenarios. The results indicate that high electron density and large off-axis deposited ECH power are crucial for obtaining negative central shear and large-radius ITBs.
Article
Instruments & Instrumentation
Yunxin Cheng, Ling Zhang, Shigeru Morita, Ailan Hu, Zhenwei Wu, Zong Xu, Yanmin Duan, Liqing Xu, Long Zhong, Fengling Zhang, Wenmin Zhang, Zihang Zhao, Weikuan Zhao, Zhengwei Li, Haiqing Liu
Summary: Two pairs of space-resolved EUV spectrometers have been newly developed to observe the radial profile of impurity line emissions and study the transport of high-Z impurity ions in EAST tokamak plasmas. The performance of these spectrometers has been substantially improved by using a CMOS detector, leading to enhanced spectral resolution, temporal resolution, and elimination of signal saturation issues.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)