Article
Physics, Fluids & Plasmas
L. Cordaro, P. Zanca, M. Zuin, F. Auriemma, A. Fassina, E. Martines, B. Zaniol, R. Cavazzana, G. De Masi, G. Grenfell, B. Momo, S. Spagnolo, M. Spolaore, N. Vianello
Summary: This study focuses on the fast, spontaneous rotation of tearing modes (TM) in RFX-mod circular tokamak discharges and identifies the reasons for the rotation slowdown.
Article
Physics, Fluids & Plasmas
I. G. Miron
Summary: The paragraph discusses the limitations of pressure-driven instabilities on the plasma normalized beta value and presents a multi-mode model for describing NTM evolution. By solving the perturbed equations in various spaces and making approximations, a linear model is proposed to provide a clear, quasi-analytic NTM solution, which has been tested against different discharges at JET.
Article
Chemistry, Multidisciplinary
Alexander Yashin, Anna Ponomarenko, Ivan Balachenkov, Gleb Kurskiev, Evgenii Kiselev, Vladimir Minaev, Alexander Petrov, Yury Petrov, Nikolay Sakharov, Nikita Zhiltsov
Summary: In this study, we observed magnetohydrodynamic (MHD) activity of the spherical tokamak Globus-M2, which resulted in a deterioration in plasma confinement and a transition from H-mode to L-mode or disruption. The observed instability was identified as tearing modes caused by the formation of magnetic islands in plasma, which impose limits on plasma pressure. The width and velocity of the islands play crucial roles in their impact on plasma confinement. The Doppler backscattering (DBS) method combined with magnetic probes was used to study tearing modes in the spherical tokamak Globus-M2. Comparative analysis of the observed tearing modes and the influence of different plasma parameters on their development was conducted.
APPLIED SCIENCES-BASEL
(2023)
Article
Physics, Fluids & Plasmas
S. S. Lu, Z. W. Ma, W. Tang, W. Zhang, Y. Liu
Summary: The study on the nonlinear dynamics of the m/n = 2/1 double tearing mode (DTM) in ITER shows that explosive bursts occur only with moderate separation or strong magnetic shear strength between the two rational surfaces. In cases of large separation and weak shear strength between the two rational surfaces, the magnetic islands saturate without strong interaction with each other.
Review
Multidisciplinary Sciences
Huishan Cai, Ding Li
Summary: This review focuses on the interaction between energetic particles and tearing modes in magnetically confined fusion plasmas. The influence of energetic particles on tearing modes and the transport of energetic particles by tearing modes are discussed. The effects of energetic particles on tearing modes are described based on a general dispersion relation, while the transport of energetic particles is reviewed for both circulating and trapped particles. The importance of this interaction and open issues are also discussed.
NATIONAL SCIENCE REVIEW
(2022)
Article
Physics, Multidisciplinary
Hao Bao-Long, Chen Wei, Li Guo-Qiang, Wang Xiao-Jing, Wang Zhao-Liang, Wu Bin, Zang Qing, Jie Yin-Xian, Lin Xiao-Dong, Gao Xiang
Summary: This study focuses on the confinement of fusion born alpha particles in tokamak, calculating the alpha particle loss induced under perturbation of ripple and neoclassical tearing mode (NTM). The main findings include that collisionless stochastic ripple diffusion is the main loss channel in CFETR, ripple perturbation has no influence on passing particles, and the synergistic effect is negligible with NTM perturbation amplitude increasing.
ACTA PHYSICA SINICA
(2021)
Article
Physics, Fluids & Plasmas
R. J. La Haye, C. Chrystal, E. J. Strait, J. D. Callen, C. C. Hegna, E. C. Howell, M. Okabayashi, R. S. Wilcox
Summary: New studies have identified the critical parameters and physics governing the onset of disruptive neoclassical tearing mode (NTM). The research shows that an m/n = 2/1 mode can destabilize an otherwise stable NTM under certain conditions. These findings have important implications for future experiments such as ITER, providing guidance for control and prediction.
Article
Physics, Fluids & Plasmas
L. Bardoczi, R. J. La Haye, E. J. Strait, N. C. Logan, S. P. Smith, N. J. Richner, J. D. Callen
Summary: We have successfully achieved preemptive direct stabilization of m, n = 2, 1 neoclassical tearing modes (NTMs) in DIII-D low-torque ITER baseline scenario plasmas using electron cyclotron waves. The experiments demonstrate that the observed stabilization is achieved by replacing the missing bootstrap current in the island with electron cyclotron current drive (ECCD). These findings are significant as they provide the first demonstration of disruptive NTM control by ECCD in the plasma scenario planned for ITER.
Article
Physics, Fluids & Plasmas
T. Bando, T. Wakatsuki, M. Honda, A. Isayama, K. Shinohara, S. Inoue, M. Yoshida, G. Matsunaga, M. Takechi, N. Oyama, S. Ide
Summary: The study investigated the suppression of sawtooth collapse in JT-60U through the stabilization of the m/n = 2/1 NTM without ELMs. It was observed that during the stabilization of the m/n = 2/1 NTM, there was modulation in the toroidal rotation velocity with the frequency of the n = 1 HC.
PLASMA PHYSICS AND CONTROLLED FUSION
(2021)
Article
Physics, Fluids & Plasmas
Xu Yang, Yueqiang Liu, Wei Xu, Yuling He, Guoliang Xia
Summary: The influence of negative triangularity (NT) on the stability of the n = 1 tearing mode (TM) has been investigated numerically. The TM near the plasma edge is found to be more unstable in NT plasmas compared to positive triangularity (PT) plasmas, due to the lack of favorable average curvature stabilization in NT configurations. However, in the core-localized TM, larger Shafranov shift in the plasma core associated with NT configuration results in more stable TM.
Article
Physics, Fluids & Plasmas
A. Gude, M. Maraschek, V Igochine, B. Sieglin, M. Willensdorfer, H. Zohm
Summary: Tearing modes are a major concern for large tokamak devices, and their detection and characterization are crucial to avoid impact on discharge or machine damage. The phase difference between different modes affects mode detection and identification, while phase-locked tearing modes can be in phase at any poloidal position.
PLASMA PHYSICS AND CONTROLLED FUSION
(2021)
Article
Computer Science, Interdisciplinary Applications
W. Zhang, S. C. Jardin, Z. W. Ma, A. Kleiner, H. W. Zhang
Summary: By comparing the simulation results of CLT code and M3D-C1 code, it was found that they were almost identical in terms of resistive kink mode and tearing mode, including linear and nonlinear growth rates. This indicates that the simulation results for the 1/1 resistive-kink mode and 2/1 tearing mode are accurate and reliable.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Physics, Fluids & Plasmas
Ruo Jia, Da Li, Yonghua Ding, Zhengkang Ren, Nengchao Wang, Feiyue Mao, Ying He
Summary: It has been found through experiments that a higher-frequency rotating resonant magnetic perturbation (RRMP) can suppress a large tearing mode (TM) and avoid subsequent disruption. Further investigation reveals a notable linear relationship between changes in the TM amplitude and the flow shear, suggesting that the flow shear plays a significant role in the suppression of TMs and offers a plausible method to prevent disruptions in future devices.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Physics, Fluids & Plasmas
L. Bardoczi, N. J. Richner, N. C. Logan
Summary: Analysis of a multi-scenario database of over 13,000 DIII-D H-mode discharges shows that magnetic islands are predominantly pressure gradient driven and stochastically triggered non-linear instabilities. The observations suggest that the majority of the analyzed 2,1 tearing modes are non-linear, neoclassically driven instabilities, with classical stability not playing a dominant role in their onset.
Article
Physics, Fluids & Plasmas
Yuling He, Yueqiang Liu, Li Li, Xu Yang, Guoliang Xia
Summary: The study investigates magnetic feedback stabilization of the tearing mode and finds that the combination of internal active coils and internal sensors achieves optimal control. In the presence of favorable curvature effects, the closed-loop tearing index becomes complex-valued, partly due to interaction with the dissipative wall eddy current response.
PLASMA PHYSICS AND CONTROLLED FUSION
(2021)
Article
Nanoscience & Nanotechnology
W. Zhang, Z. W. Ma, Y. Zhang, J. Zhu
Article
Physics, Fluids & Plasmas
W. Zhang, Z. W. Ma, H. W. Zhang, J. Zhu
PHYSICS OF PLASMAS
(2019)
Article
Physics, Fluids & Plasmas
W. Zhang, Z. W. Ma, J. Zhu, H. W. Zhang
PLASMA PHYSICS AND CONTROLLED FUSION
(2019)
Article
Physics, Fluids & Plasmas
W. Zhang, Z. W. Ma, H. W. Zhang, X. Wang
PLASMA PHYSICS AND CONTROLLED FUSION
(2020)
Article
Physics, Fluids & Plasmas
W. Zhang, Z. W. Ma, F. Porcelli, H. W. Zhang, X. Wang
Article
Physics, Fluids & Plasmas
W. Zhang, Z. W. Ma, X. Q. Lu, H. W. Zhang
Article
Nuclear Science & Technology
W. Zhang, Z. W. Ma, H. W. Zhang
Summary: The study found that the fast pressure crash associated with DTMs is not directly linked to their explosive growth, which occurs earlier in the nonlinear phase, while the pressure crash happens later in the nonlinear stage. Additionally, it was observed that the radial flow plays a crucial role in transferring hot plasma around the magnetic axis to the outer region, leading to the fast pressure crash.
JOURNAL OF FUSION ENERGY
(2020)
Article
Physics, Fluids & Plasmas
W. Zhang, X. Lin, Z. W. Ma, X. Q. Lu, H. W. Zhang
PHYSICS OF PLASMAS
(2020)
Article
Computer Science, Interdisciplinary Applications
W. Zhang, S. C. Jardin, Z. W. Ma, A. Kleiner, H. W. Zhang
Summary: By comparing the simulation results of CLT code and M3D-C1 code, it was found that they were almost identical in terms of resistive kink mode and tearing mode, including linear and nonlinear growth rates. This indicates that the simulation results for the 1/1 resistive-kink mode and 2/1 tearing mode are accurate and reliable.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Physics, Fluids & Plasmas
W. Zhang, Z. W. Ma, H. W. Zhang
Summary: In this study, the nonlinear resistive-kink mode in low resistivity plasma in tokamak was investigated using a 3D, toroidal, nonlinear Hall-MHD code. It was discovered that the effect of two-fluid dynamics and toroidal flow can significantly alter the behavior of the resistive-kink mode, leading to a different evolution of magnetic islands and reconnection processes. Additionally, the investigation into the toroidal effect showed that the widths of the main m/n = 1/1 island and the secondary island slightly increase with increasing aspect ratios.
Article
Physics, Fluids & Plasmas
W. Zhang, Z. W. Ma, H. W. Zhang, W. J. Chen, X. Wang
Summary: In this paper, we systematically investigate the nonlinear evolution of the resistive kink mode in the low resistivity plasma in Tokamak geometry. We find that the aspect ratio of the initial equilibrium can significantly influence the critical resistivity for plasmoid formation. Additionally, the critical resistivity for plasmoid formation decreases with increasing plasma viscosity in the moderately low resistivity regime. The geometry of Tokamaks also affects the critical resistivity for plasmoid formation.
Article
Physics, Fluids & Plasmas
Wei Zhang, Zhiwei Ma, Haowei Zhang, Xin Wang
Summary: The study numerically investigates the sawtooth-like oscillations resulting from the m/n = 2/1 double tearing mode. It finds that the behavior of the oscillations is influenced by the perpendicular thermal conductivity and external heating rate. The steady state with m/n = 2/1 radial flow might be beneficial for future fusion reactors.
PLASMA SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
W. Zhang, Z. W. Ma, X. Wang, W. J. Chen
Summary: Numerical investigations have been conducted on pressure crashes with a low magnetic shear profile in Tokamaks using a three-dimensional, toroidal, and nonlinear MHD code CLT. Three different types of pressure crashes have been identified, including the formation and merging of cold bubbles into the hot core, the formation of two cold bubbles squeezing the hot core, and the growth of a magnetic island filling up the central region. The thresholds for these pressure crashes are systematically discussed.
PHYSICS OF PLASMAS
(2022)
Article
Physics, Fluids & Plasmas
Yan Chao, Wei Zhang, Liqun Hu, Kangning Geng, Liqing Xu, Tao Zhang, Qing Zang, Tianfu Zhou
Summary: A new long-pulse high electron temperature regime is achieved on the experimental advanced superconducting tokamak (EAST) using pure radio frequency heating. This regime involves two confinement states related to two magneto-hydrodynamic (MHD) modes, one of which is identified as the m/n = 1/1 kink mode. The frequency evolution of the kink mode is studied using the three-dimensional, toroidal, and nonlinear Hall-MHD code CLT. It is found that the frequency of the m/n = 1/1 kink mode significantly increases during each sawtooth crash, which is confirmed by experimental data.
PLASMA SCIENCE & TECHNOLOGY
(2023)
