Development of a new gas puff imaging diagnostic on the HL-2A tokamak

Yuan, Bin; Xu, M.; Yu, Yijun; Zang, L.; Hong, Rongjie; Chen, C.; Wang, Z.; Nie, Lin; Ke, Rui; Guo, Dong; Wu, Yifan; Long, Ting; Gong, Shuwen; Liu, Hongbin; Ye, M.; Duan, Xingwu; Team, Hl A

doi:10.1088/1748-0221/13/03/c03033

Cited by 15 publications

(11 citation statements)

References 19 publications

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“…A CO 2 dispersion interferometer [50] and a high sensitivity far-infrared laser interferometer [23] were developed for measuring the line-averaged density in time. The diagnostics for measuring density fluctuation were developed, including phase contrast imaging [51][52][53], beam emission spectroscopy [54,55] and He gas-puff imaging [56].…”

Section: Discussionmentioning

confidence: 99%

Overview of HL-2A recent experiments

Xu¹,

Duan²,

Liu³

et al. 2019

Nucl. Fusion

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ITER and to the advanced tokamak operation (e.g. the operation of future HL-2M), such as the access of H-mode, energetic particle physics, edge-localized mode (ELM) mitigation/suppression and disruption mitigation. Since the 2016 Fusion Energy Conference, the HL-2A team has focused on the investigations on the following areas: (i) pedestal dynamics and L-H transition, (ii) techniques of ELM control, (iii) the turbulence and transport, (iv) energetic particle physics. The HL-2A results demonstrated that the increase of mean E × B shear flow plays a key role in triggering L-I and I-H transitions. While the change of E × B flow is mainly induced by the ion pressure gradient. Both mitigation and suppression of ELMs were realized by laser blow-off (LBO) seeded impurity (Al, F e, W). The 30% N e mixture supersonic molecular beam injection (SMBI) seeding also robustly induced ELM mitigation. The ELMs were mitigated by low-hybrid current drive (LHCD). The stabilization of m/n=1/1 ion fishbone activities by electron cyclotron resonance heating (ECRH) was found on the HL-2A. A new m/n=2/1 ion fishbone activity was observed recently, and the modelling indicated that passing fast ions dominantly contribute to the driving of 2/1 fishbone. The non-linear coupling between toroidal Alfven eigenmode (TAE) and tearing mode (TM) leads to the generation of a high frequency mode with the toroidal mode number n=0. The turbulence is modulated by tearing mode when the island width exceeds a threshold and the modulation is localized merely in the inner area of the islands. Meanwhile, turbulence radially spreading takes place across the island region.

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Section: Discussionmentioning

confidence: 99%

Overview of HL-2A recent experiments

Xu¹,

Duan²,

Liu³

et al. 2019

Nucl. Fusion

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“…Jinbang Yuan presented the gas puff imaging (GPI) diagnostic which is developed to measure high resolution data on the spatiotemporal structure of the edge turbulence on HL-2A tokamak. The temporal resolution is up to 10 us, while the spatial resolution is 1.25-2.5 mm [24]. The measurement shows that various blob structures and motions are measured in the radial versus poloidal plane.…”

Section: Turbulence Diagnostic Developmentmentioning

confidence: 87%

“…The sudden drop of turbulence intensity clearly appears when the density increases and the plasma condition changes from the attached phase to the detached phase. Jingbang Yuan presented the measurement of the blob structures around separatrix with GPI diagnostic [24]. It is found that the positive blob structure is born inside the separatrix.…”

Section: Progress In Rmp Physics Studiesmentioning

confidence: 99%

Summary of the 8th Asia-Pacific Transport Working Group (APTWG) Meeting

Shi

Cheng

et al. 2019

Nucl. Fusion

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This conference report gives a summary on the contributed papers and discussions presented at the 8th Asia-Pacific Transport Working Group Meeting held at the Engineering & Technical College of Chengdu University of Technology, Leshan, China, from 12 to 15 June 2018. The objective of the meeting is to develop a predictive understanding of the physical mechanisms responsible for particle, energy and momentum transport in magnetically confined plasmas. In order to achieve this objective, five technical working groups were organized under the headings: (A) edge/SOL turbulence and L-H/H-L transition, (B) core-edge turbulence coupling, and transport in high beta plasmas, (C) transport and turbulence in 3D magnetic topology, (D) interaction between energetic particles, MHD instabilities and turbulence, and (E) model reduction and experiments for validation. A summary of the selected significant progresses from the presentations in the five technical working groups is given. The Young Researchers Forum which was held in this meeting is described.

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“…Two-dimensional (2D) imaging technology is applied to the measurement of edge turbulence structure and its propagation velocity. Several 2D diagnostics for turbulence structure have been developed, including beam emission spectroscopy (BES) [4][5][6], Langmuir probe [7][8][9], electron cyclotron emission imaging (ECEI) [10][11][12][13][14] and gas puff imaging (GPI) [15][16][17]. The Langmuir probe array inserted into the edge plasma can measure floating potentials and ion saturation current directly, providing the turbulence information with high temporal evolution [18].…”

Section: Introductionmentioning

confidence: 99%

Development of a 2D spatial displacement estimation method for turbulence velocimetry of the gas puff imaging system on EAST

LI 李,

LIU 刘,

YAN 颜

et al. 2024

Plasma Sci. Technol.

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The gas puff imaging (GPI) diagnostic has been developed and operated on EAST since 2012, and the time-delay estimation (TDE) method is used to derive the propagation velocity of fluctuations from the two-dimensional GPI data. However, the TDE method is difficult to analyze the data with fast transient events, such as edge-localized mode (ELM). In consequence, a method called the spatial displacement estimation (SDE) algorithm is developed to estimate the turbulence velocity with high temporal resolution. Based on the SDE algorithm, we make some improvements, including an adaptive median filter and super-resolution technology. After the development of the algorithm, a straight-line movement and a curved-line movement are used to test the accuracy of the algorithm, and the calculated speed agrees well with preset speed. This SDE algorithm is applied to the EAST GPI data analysis, and the derived propagation velocity of turbulence is consistent with that from the TDE method, but with much higher temporal resolution.

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Development of a new gas puff imaging diagnostic on the HL-2A tokamak

Cited by 15 publications

References 19 publications

Overview of HL-2A recent experiments

Overview of HL-2A recent experiments

Summary of the 8th Asia-Pacific Transport Working Group (APTWG) Meeting

Development of a 2D spatial displacement estimation method for turbulence velocimetry of the gas puff imaging system on EAST

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