Article
Physics, Fluids & Plasmas
R. Fitzpatrick
Summary: This study calculates the critical error-field amplitudes for triggering error-field penetration in ITER and SPARC ohmically heated plasmas. It finds that at normal operating electron number density, diamagnetic levels of rotation are sufficient to protect the plasmas from m = 2 / n = 1 error-field penetration, but higher values of n may still induce penetration. Moreover, the plasmas are more susceptible to error-field penetration when the electron fluid at the rational surface rotates in the ion diamagnetic direction. The threshold for error-field penetration increases with increasing density in the low-density linear Ohmic confinement regime, but levels off once the plasma enters the high-density saturated Ohmic confinement regime.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
Cheng Ye, You-Wen Sun, Hui-Hui Wang, Yue-Qiang Liu, Tong-Hui Shi, Qing Zang, Tian-Qi Jia, Qun Ma, Shuai Gu, Nan Chu, Kai-Yang He, Man-Ni Jia, Xue-Min Wu, Peng-Cheng Xie, Hui Sheng, Hua Yang, Lian-Sheng Huang, Biao Shen, Miao-Hui Li, Jin-Ping Qian, EAST Team
Summary: The plasma-beta effect on the n=1 resonant magnetic perturbation (RMP) field penetration in purely radio-frequency (RF) wave heated discharges has been investigated. The experimental results show that the error-field tolerance is improved with increasing RF power, benefiting from the increased electron perpendicular flow dominated by a counter-current electron diamagnetic flow. However, the theoretical scaling overestimates the power index, and the degradation effect of plasma beta is observed.
Article
Physics, Fluids & Plasmas
Cheng Ye, You-Wen Sun, Hui-Hui Wang, Zheng-Xiong Wang, Lai Wei, Qun Ma, Qing Zang, Shuai Gu, Kai-Yang He, Nan Chu, Xue-Min Wu, Peng-Cheng Xie, Hui Sheng, Zhi-Cai Sheng, Biao Shen, Ying-Jie Chen
Summary: This study investigates the density scaling of n = 1 error field penetration in RF-dominant heated L-mode discharges in the EAST tokamak. It is found that the density scaling of the threshold field strength for error field penetration in LHCD plasmas is weaker compared to previous ohmic heated discharges. The observed scaling is consistent with MHD theory on error field penetration and is validated through numerical investigations in various tokamak operational regimes.
Article
Physics, Fluids & Plasmas
S. M. Yang, J. -K. Park, Y. S. Na, Y. In, H. Hahn, J. W. Jeon, J. W. Yoo, W. H. Ko, K. D. Lee, J. H. Lee, J. W. Lee, S. C. Hong, Y. J. Shi, N. C. Logan, Q. Hu, G. J. Choi
Summary: This study investigates the sensitivity of error field threshold in global parameters and toroidal harmonics dependence in KSTAR L-mode plasmas. The results show a non-monotonic correlation between error field threshold and density, which can be attributed to a modification of existing theoretical scaling in SOC and the influence of plasma rotation.
Article
Physics, Fluids & Plasmas
Jie Ren, You-Wen Sun, Hui-Hui Wang, Shuai Gu, Jin-Ping Qian, Tong-Hui Shi, Biao Shen, Yue-Qiang Liu, Wen-Feng Guo, Nan Chu, Kai-Yang He, Man-Ni Jia, Yong Wang, Zhi-Cai Sheng, Zheng-Ping Luo, Long Zeng, Xian-Zu Gong, Yun-Feng Liang, Bao-Nian Wan
Summary: This study investigates the penetration of n = 2 magnetic field perturbations in an ohmic heating plasma, showing that the n = 2 mode often stimulates an n = 1 mode. The evolution of the n = 1 mode involves an initial small island growth stage and a later saturation stage, with the phase being a key factor in the interactions between the two modes.
Article
Physics, Fluids & Plasmas
G. Miron, F. Rimini
Summary: A model is needed to provide the dynamic evolution of the intrinsic magnetic error fields amplitude in tokamaks, in order to develop strategies to correct its destabilizing effect.
Article
Physics, Fluids & Plasmas
C. Paz-Soldan, Q. Hu, N. C. Logan, J-K Park
Summary: A technique to identify intrinsic error fields (EFs) in tokamaks with minimized risk of disruption is demonstrated on the DIII-D tokamak. The method extends the conventional driven magnetic island 'compass scan' approach by modifying asynchronous control waveforms to enable prompt healing of the island instability. This technique can be suitable for plasma-based EF identification in the early commissioning stages of future disruption-averse tokamaks.
Article
Physics, Fluids & Plasmas
Feiyue Mao, Nengchao Wang, Zhuo Huang, Zhengkang Ren, Song Zhou, Chengshuo Shen, Xiaoyi Zhang, Ying He, Qi Zhang, Ruo Jia, Chuanxu Zhao, Yangbo LI, Bo Hu, Da LI, Abba Alhaji Bala, Zhipeng Chen, Zhongyong Chen, Zhoujun Yang, Yunfeng Liang, Yonghua Ding, Yuan Pan
Summary: The spectrum effect on the penetration of resonant magnetic perturbation (RMP) is studied with upgraded in-vessel RMP coils on J-TEXT. It is found that the type of RMP penetration relates to the phase difference between the upper and lower coil rows. The amplitudes of 2/1 and 3/1 RMP components can be varied by this phase difference.
PLASMA SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
V. I. Ilgisonis, V. P. Lakhin, N. A. Marusov, A. Smolyakov, E. A. Sorokina
Summary: The nonlocal eigenmode analysis of low-frequency zonal flows is conducted in toroidally rotating tokamak plasmas using a simplified one-fluid ideal magnetohydrodynamic model. It is found that under typical plasma parameter profiles, toroidal plasma rotation leads to the formation of global zonal flows on the periphery of the plasma column. For certain equilibria, these zonal flows are aperiodically unstable, resulting in the excitation of differential plasma rotation at the edge of the tokamak plasma.
Article
Physics, Fluids & Plasmas
Xingquan Wu, Guosheng Xu, Ning Yan, Ran Chen, Liang Wang, Baonian Wan
Summary: The study shows that in a tokamak plasma system, controlling the intensity and position of S(eff) can offset the impact of L(SOL) on density profiles, leading to the formation of SOL density shoulders.
Article
Physics, Fluids & Plasmas
Ruirui Ma, Liu Chen, Fulvio Zonca, Yueyan Li, Zhiyong Qiu
Summary: This study theoretically investigates the linear wave properties of low-frequency Alfven modes (LFAMs) observed in DIII-D tokamak experiments and finds that LFAM is a reactive-type kinetic ballooning mode instability under certain experimental conditions. The study also explains the observed spectral patterns and the dependence of instability drive on electron temperature in the experiments.
PLASMA PHYSICS AND CONTROLLED FUSION
(2022)
Article
Physics, Multidisciplinary
V Solokha, M. Groth, G. Corrigan, S. Wiesen
Summary: Experiments in JET show that the density limit in pure hydrogen plasmas is approximately 20% higher than in deuterium plasmas, primarily due to the lower density of hydrogen atoms at the separatrix. Additionally, more efficient dissociation and ionization of hydrogen molecules and atoms occur at the high-field X-point region, leading to a higher density limit in hydrogen plasmas compared to deuterium plasmas under certain conditions.
Article
Physics, Fluids & Plasmas
A. Kryzhanovskyy, D. Bonfiglio, S. Cappello, M. Veranda, M. Zuin
Summary: This paper discusses the properties and triggering mechanisms of Alfven waves in the reversed-field pinch (RFP) and circular tokamak configurations using nonlinear 3D magnetohydrodynamics (MHD) modeling. Numerical simulations and comparisons with analytical solutions are performed, providing consistent results with experimental observations.
Article
Nuclear Science & Technology
K. Ahmad, Z. Ahmad, M. Bilal, M. Taimoor
Summary: The tokamak is widely accepted among the fusion community for future fusion reactors. Eddy currents are crucial for its steady-state operation and can be mitigated through experimental and simulation tools, optimizing startup scenarios.
FUSION ENGINEERING AND DESIGN
(2021)
Article
Physics, Fluids & Plasmas
J. W. Liu, Q. Zang, Y. Liang, Y. H. Huang, E. Z. Li, L. Q. Xu, A. Knieps, Y. Q. Chu, Y. Chao, Y. C. Hu, Y. F. Jin, H. Q. Liu, H. L. Zhao, B. Lyu, X. Z. Gong, EAST Team
Summary: A very high core electron temperature plasma has been successfully established and sustained in EAST by using both LHW and ECRH. Power balance analysis shows that increasing ECRH power can significantly change the temperature gradient in the plasma core region, and there is a strong synergistic effect between ECRH and LHW. Furthermore, three distinguishable stages have been observed in the density ramp-up, and the formation of an internal plasma density transport barrier has been observed during the transition between the stages.
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2016)
Article
Physics, Fluids & Plasmas
B. Tobias, M. Chen, I. G. J. Classen, C. W. Domier, R. Fitzpatrick, B. A. Grierson, N. C. Luhmann, C. M. Muscatello, M. Okabayashi, K. E. J. Olofsson, C. Paz-Soldan
PHYSICS OF PLASMAS
(2016)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2016)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2017)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2017)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2017)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2018)
Article
Physics, Fluids & Plasmas
Dov J. Rhodes, A. J. Cole, D. P. Brennan, J. M. Finn, M. Li, R. Fitzpatrick, M. E. Mauel, G. A. Navratil
PHYSICS OF PLASMAS
(2018)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2014)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2018)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2018)
Article
Physics, Fluids & Plasmas
Tao Xu, Richard Fitzpatrick
Article
Physics, Fluids & Plasmas
Ryan L. White, Richard Fitzpatrick
PHYSICS OF PLASMAS
(2015)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2015)
Article
Physics, Fluids & Plasmas
Richard Fitzpatrick
PHYSICS OF PLASMAS
(2015)