Impact of impurity mixture gas seeded by supersonic molecular beam injection on edge-localized modes in the HL-2A tokamak

Zhong, W.L.; Zou, X.L.; Feng, B.B.; Xiao, Guoliang; Liang, Anshu; Yang, Z.C.; Chen, C.Y.; Gao, Jinming; Cheng, J.; Zhang, Y.P.; Wang, T.B.; Han, Mingkun; Wang, Z.X.; Xiao, W.W.; Liu, L.; Jiang, M.; Shi, P.W.; Wen, Jie; Cui, Z.Y.; Dong, Chengli; Liu, C.H.; Wang, Z.H.; Song, X.M.; Yan, L.W.; Dong, J. Q.; Ding, X.T.; Yu, D.L.; Shi, Z.B.; Liu, Yi; Yang, Qingwei; Xu, M.; Duan, X.R.

doi:10.1088/1741-4326/ab1d7a

Cited by 27 publications

(20 citation statements)

References 99 publications

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“…The IM turbulence induced impurity ion influx is demonstrated to be higher for a higher τ i = T e /T i . Interestingly, these theoretical predictions are in coincidence with the evidence observed in argon injection experiment on HL-2A tokamak [39]. The experimental observation that a lower electron density gradient is favorable for sustainment of HDPs of impurity ions is verified in turn with simulation.…”

Section: Introductionsupporting

confidence: 81%

Impurity mode induced turbulent particle transport and its temperature screening effect

et al. 2021

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Turbulent transport of impurity ions with hollow density profiles (HDPs), which are widely observed in magnetically confined plasmas and desirable for fusion reactor, is self-consistently investigated. A full gyrokinetic description is employed for main and impurity ions. Instead of conventional ion temperature gradient (ITG, including impurity ITG) and trapped electron modes (TEMs), impurity modes (IMs), driven by impurity ion density gradient opposite to that of electrons, are considered. The impurity ion flux induced by IMs is shown to be approximately one order of magnitude higher than that induced by TEMs when both kinds of modes coexist. Main ITG and electron temperature gradient (ETG) are found to reduce influx of impurity ions significantly, resembling temperature screening effect of neoclassical transport of impurity ions. The simulation results such as peaking factor of the HDPs and the effects of main ITG are found in coincidence with the evidence observed in argon injection experiment on HL-2A tokamak. Thus, the IM turbulence is demonstrated to be a plausible mechanism for the transport of impurity ions with HDPs. A strong main ITG, ETG, and a low electron density gradient are expected to be beneficial for sustainment of HDPs of impurity ions and reduction of impurity accumulation in core plasma.

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Section: Introductionsupporting

confidence: 81%

Impurity mode induced turbulent particle transport and its temperature screening effect

et al. 2021

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“…The above simulation results are evidenced for the first time in an argon injection experiment [45,46]. Figure 15 presents the radial profile of the radiation intensity I rad (a), the temporal evolutions of R/L Ti and R/L Te (b), IM turbulence intensity S integrated over 40-90 kHz (c), and the normalized density gradient of argon ions R/L nz (d) and electrons R/L ne (e), and the fluctuation intensity S and γ/ω * e of IM versus R/L nz ( f ).…”

Section: Impurity Mode Induced Turbulent Particle Transportsupporting

confidence: 52%

Progress of HL-2A experiments and HL-2M program

Duan¹,

Xu²,

Zhong³

et al. 2022

Nucl. Fusion

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Since the last IAEA Fusion Energy Conference in 2018, significant progress of the experimental program of HL-2A has been achieved on developing advanced plasma physics, edge localized mode (ELM) control physics and technology. Optimization of plasma confinement has been performed. In particular, high-N H-mode plasmas exhibiting an internal transport barrier have been obtained (normalized plasma pressure N reached up to 3). Injection of impurity improved the plasma confinement. ELM control using resonance magnetic perturbation (RMP) or impurity injection has been achieved in a wide parameter regime, including Types I and III. In addition, the impurity seeding with supersonic molecular beam injection (SMBI) or laser blow-off (LBO) techniques has been successfully applied to actively control the plasma confinement and instabilities, as well as the plasma disruption with the aid of disruption prediction. Disruption prediction algorithms based on deep learning are developed. A prediction accuracy of 96.8% can be reached by assembling convolutional neural network (CNN). Furthermore, transport resulted from a wide variety of phenomena such as energetic particles and magnetic islands have been investigated. In parallel with the HL-2A experiments, the HL-2M mega-ampere class tokamak was commissioned in 2020 with its first plasma. Key features and capabilities of HL-2M are briefly presented.

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“…The corresponding number of the injected particles is 8.3 × 10 18 . The impurity particles are mainly deposited at the edge plasma region [37]. The fueling effect on the plasma is negligible, as figure 5(b) shows that the SMBI does not obviously increase the plasma density.…”

Section: Response Of Elms and Pedestal To Smbi-seeded Neon Gas Impuritymentioning

confidence: 93%

Enhancement of plasma ion temperature by impurity seeding in H-mode plasmas

Xue¹,

Zhong²,

Zou³

et al. 2021

Nucl. Fusion

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Effect of impurity seeding on plasma global confinement has been investigated in H-mode plasmas of the HL-2A tokamak. Metal and gas impurities can be externally seeded by laser blow-off (LBO) and supersonic molecular beam injection (SMBI) systems, respectively. Using the LBO system to seed aluminium impurities into H-mode plasmas, it is observed that the ELM frequency after the impurity seeding is reduced by about 50%. The plasma stored energy is enhanced. The corresponding energy loss caused by each ELM increases with the decrease of ELM frequency. Besides, the neon and argon gas impurities have been seeded into H-mode plasmas by SMBI. The ELM frequency decreases to 0.3–0.5 times lower than that before the SMBI. The prolonged inter-ELM periods allow the plasma to build a higher pedestal density. It is observed that the energy confinement of the H-mode plasma is improved by the edge-deposited impurities, which is mainly attributed to the enhancement of plasma ion temperature. Both the edge and core ion temperatures are increased by 20%–40% after the impurity seeding. The quasi-linear simulations predict that the ion heat flux induced by ion temperature gradient mode is deceased in the present of impurity. The result suggests that the seeded impurity could reduce the edge ion thermal transport, resulting in the formation a higher edge ion temperature, which is a boundary condition for further increasing the core temperature through the profile stiffness.

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Impact of impurity mixture gas seeded by supersonic molecular beam injection on edge-localized modes in the HL-2A tokamak

Cited by 27 publications

References 99 publications

Impurity mode induced turbulent particle transport and its temperature screening effect

Impurity mode induced turbulent particle transport and its temperature screening effect

Progress of HL-2A experiments and HL-2M program

Enhancement of plasma ion temperature by impurity seeding in H-mode plasmas

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