Mitigation of long-lived modes by lower hybrid wave on the HL-2A tokamak

Shi, P.W.; Zhu, Xiaolong; Liang, Anshu; Chen, Wei; Shi, Z.B.; Wang, Tianbo; Yang, Z.C.; Yu, Liming; Jiang, M.; He, Xiaoxue; Ji, Xiao; Zhong, Weizhi; Xu, M.; Wang, Jialei; Duan, X.R.

doi:10.1088/1741-4326/ac8691

Cited by 6 publications

(4 citation statements)

References 40 publications

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“…While in H-mode, the density fluctuation is decreased compared to the L-mode and I-mode. It should be noted that the spikes at around f ∼ 20 kHz are long lived mode (LLM), which is driven by plasma pressure gradient, and has the mode numbers of m/n = 1/1 [46,47]. Figure 3(e) shows the radial distribution of WCM amplitude.…”

Section: Features Of Wcmmentioning

confidence: 99%

Identification of I-mode with ion ITB in NBI-heated plasmas on the HL-2A tokamak

Liang

Zou²,

Zhong³

et al. 2023

Nucl. Fusion

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I-mode has been observed on the HL-2A tokamak. The I-mode features an edge transport barrier (ETB) in electron temperature and an L-mode like edge density. A weakly coherent mode (WCM) is observed in the edge region with the frequency of f ~ 60 - 160 kHz and the poloidal wavenumber of kθ ~ 0.5 - 2.5 cm-1. The maximum of WCM amplitude is located near the top of electron temperature pedestal. A critical value of E×B velocity shear for triggering the L-I transition has been found, and is much lower than that for triggering the L-H transition. Additionally, ion internal transport barrier (ITB) has been observed in the I-mode. The formation of ion ITB is due to the increase of E×B velocity shear, leading to the suppression of turbulence. Transport analysis further confirms the existence of electron ETB and ion ITB. The coexistence of electron ETB and ion ITB leads to an improved plasma confinement, which is comparable to that in the H-mode, suggesting that I-mode with ITB regimes could be an interesting operation scenario for future fusion devices.

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Section: Features Of Wcmmentioning

confidence: 99%

Identification of I-mode with ion ITB in NBI-heated plasmas on the HL-2A tokamak

Liang

Zou²,

Zhong³

et al. 2023

Nucl. Fusion

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“…型 [26] , 模型中跟踪了磁约束聚变等离子体的非线性演化, 主要包括模幅度和快粒子分布函数的非线性自洽演化, 采用完整的电阻磁流体方程来表述背景等离子体和漂移动理学方程来描述快粒子效应. 中许多重要的物理现象, 例如快粒子激发的环向阿尔芬本征模 [27] 以及环向阿尔芬本征模雪崩 [28] 、长寿模 [29] 、锯齿模 [30] 、鱼骨模 [31,32] 、比压阿尔芬本征模 [33] 、阿尔芬级联模 [34,35] 、鱼骨模与内部输运垒的相互作用 [36] 等.…”

Section: 数值模型和参数设置unclassified

Hybrid numerical simulation on fast particle transport induced by synergistic interaction of low- and medium-frequency magnetohydrodynamic instabilities in tokamak plasma

Zhu¹,

Chen²,

Feng³

et al. 2023

Acta Phys. Sin.

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In tokamak experiments, various MHD instabilities usually co-exist and interact with fast particles. It can cause significant fast particle transport and loss, and pose damage to the first wall, leading to discharge quench in tokamak. Therefore, understanding the physical mechanism of fast particle transport caused by MHD instabilities is a crucial but urgently solved physical issue for the steady-state long pulse operation of future reactor-graded devices. Based on the experimental phenomenon of synergy between nonresonant internal kink mode and tearing mode observed on NSTX, a spherical tokamak device, this paper utilizes the global nonlinear hybrid-kinetic simulation code M3D-K to compare the characteristics of fast particle loss, transport and redistribution in the two cases: I) only non-resonant internal kink modes; II) the synergy between the non-resonant internal kink mode and tearing mode. The physical mechanism of fast particle transport, loss and redistribution caused by such synergy is studied. The results show that the synergy between the non-resonant internal kink mode and the tearing mode can significantly enhance the loss and transport of fast particles. The main reason is that such synergy can provide a radial channel for fast particles to mitigate from the plasma core to the plasma boundary accompanied with the total stochasticity of the magnetic topology. These results can help understand the physical mechanism of the transport and loss of fast particles caused by the synergy of low-frequency MHD instabilities in future fusion reactors, and provide some new ideas for finding strategies to control and mitigate the loss and transport level of fast particles in future fusion reactors.

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“…To realize the steady state operation of future fusion reactors, a variety of auxiliary heating methods are used in many tokamak devices, such as electron cyclotron resonance heating (ECRH), ion cyclotron resonance heating (ICRH) and neutral beam injection (NBI). Meanwhile, large quantities of energy particles (EPs) are generated during the NBI heating of plasma, which affect the stability of MHD mode and form various instabilities, including long-live modes, sawteeth, fishbone and Alfvén eigenmodes [1][2][3][4][5][6][7][8]. Energetic particledriving instabilities may affect plasma confinement and alpha particle heating efficiency.…”

Section: Introductionmentioning

confidence: 99%

Simulation of non-resonant high-order harmonics energetic particle modes in tokamak plasmas

Liu,

Ren,

Yang

et al. 2024

Phys. Scr.

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Based on the parameters of the HL-2A experiment, the effect of energetic particles (EPs) on non-resonant high-order harmonics energetic particle modes (EPMs) with qmin>1 is investigated in the present work. Hybrid kinetic-magnetohydrodynamic nonlinear code M3D-K is performed to simulate the linear properties and the nonlinear evolution of the non-resonant EPM during neutral beam injection (NBI). To deeply understand the physical mechanism of interaction resonant between energetic-ions and non-resonant EPM, this work compares the effects of passing energetic particles and trapped energetic particles on the non-resonant EPM instabilities. It is numerically identified that EPs’ effects on high n harmonics (m/n = 2/2, 3/3, 4/4) instability are more obvious than the m/n = 1/1 mode. Furthermore, the effects of energetic particles injection energy, the minimum safety factor qmin , toroidal rotation and beam ion distribution on the features of high n harmonics are also investigated specifically. Toroidal rotation is found to suppress high n harmonics, which is more obvious for the modes driven by trapped particles. Nonlinear simulation results show that these non-resonant high n harmonics can induce larger energetic ion transport, which may affect the plasma confinement performance.

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Mitigation of long-lived modes by lower hybrid wave on the HL-2A tokamak

Cited by 6 publications

References 40 publications

Identification of I-mode with ion ITB in NBI-heated plasmas on the HL-2A tokamak

Identification of I-mode with ion ITB in NBI-heated plasmas on the HL-2A tokamak

Hybrid numerical simulation on fast particle transport induced by synergistic interaction of low- and medium-frequency magnetohydrodynamic instabilities in tokamak plasma

Simulation of non-resonant high-order harmonics energetic particle modes in tokamak plasmas

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