Changjian Tang

Sichuan University

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Co-Authors

Yuhong Xu

Southwest Jiaotong University

Haifeng Liu

Sichuan University

Xianqu Wang

Southwest Jiaotong University

Hai Liu

Hubei Engineering University

Jie Huang

Southwest Jiaotong University

J. Cheng

Southwest Jiaotong University

Xin Zhang

Southwest Jiaotong University

Zilin Cui

Southwest Jiaotong University

Guangjiu Lei

Southwestern Institute of Physics

Shaoyong Chen

Sichuan University

Cooperative Institutions

Institute of High Energy Physics

474

Chinese Academy of Sciences

316

University of Chinese Academy of Sciences

184

Tsinghua University

162

Sichuan University

123

University of Science and Technology of China

118

China Center of Advanced Science and Technology

102

Southwest Jiaotong University

Shanghai Jiao Tong University

Peking University

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Study of heat load and radiation distributions in EAST upgraded divertor influenced by impurity injection positions

The European Physical Journal Plus (2023)

Yang Luo Haifeng Liu Yuhong Xu Y. Feng Wenfeng Guo

Power density

Effective radiated power

10.1140/epjp/s13360-023-04199-4

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Citations (0)

Effects of negative and positive bias voltages on turbulence characteristics in J-TEXT tokamak

Plasma Physics and Controlled Fusion (2022)

Bo Zhang Hai Liu Yuhong Xu Zhipeng Chen J. Cheng

Abstract The effects of positive and negative bias voltages on the turbulence characteristics in the edge plasmas of J-TEXT are studied using Langmuir probe arrays. The experimental results illustrate that the turbulent particle transport fluxes are suppressed in both positive and negative bias cases, while the suppression mechanisms are quite different. For positive bias (+300 V), long-range correlation (LRC) structures with frequencies of about 10–30 kHz are generated, which are beneficial for turbulent transport suppression. In the −300 V bias case, no LRCs appear, while a strong mean flow shear exists which can reduce the amplitudes of potential and density fluctuations and thus decrease the turbulent transport.

Langmuir Probe

Biasing

10.1088/1361-6587/aca359

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Current reflux from an electron beam transmitted in a plasma ion channel

Physics of Plasmas (2021)

Yuxi Xia Shengpeng Yang Shaoyong Chen Changjian Tang

In this paper, the mechanism by which current reflux forms from a plasma-focused electron beam is studied theoretically and numerically by considering nonlinear interactions between the beam and plasma. We demonstrate that a moving virtual cathode can be generated at the end of a plasma ion channel due to the influence of the boundary plasma electrons on the beam, and that this accounts for reflux formation. In addition, the reflux formation condition is derived and analyzed via the beam envelope and space-charge-limited current theories. The results indicate that the virtual cathode tends to form at defocusing positions of the beam. Particle-in-cell simulations are used to verify the theoretical results and to show that the beam divergence and energy spread increase during current reflux formation.

Plasma channel

Envelope (radar)

10.1063/5.0026989

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Citations (1)

Simulation of large-scale fast neutron liquid scintillation detector

Chinese Physics C (2013)

Hao-Yang Xing Li Wang J. J. Zhu Changjian Tang Qian Yue

Neutron background measurement is always very important for dark matter detection due to almost the same effect for the recoiled nucleus scattered off by the incident neutron and dark matter particle. For deep under-ground experiments, the flux of neutron background is so low that large-scale detection is usually necessary. In this paper, by using Geant4, the relationship between detection efficiency and volume is investigated, meanwhile, two geometrical schemes for this detection including a single large-sized detector and arrayed multi-detector are compared under the condition of the same volume. The geometrical parameters of detectors are filtrated and detection efficiencies obtained under the similar background condition of China Jingping Underground Laboratory (CJPL). The results show that for a large-scale Gd-doped liquid scintillation detector, the detection efficiency increases with the size of detector at the beginning and then trends toward a constant. Under the condition of the same length and cross section, the arrayed multi-detector has almost similar detection performance as the single large-sized detector, while too much detector number could cause degeneration of detection performance. Considering engineering factors, such as testing, assembling and production, the 4×4 arrayed detector scheme is flexible and more suitable. Furthermore, the conditions for using fast and slow signal coincidence detection and the detectable lower limit of neutron energy are evaluated by simulating the light process.

Neutron Detection

Liquid Scintillation Counting

10.1088/1674-1137/37/2/026003

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Citations (3)

Magnetic Configuration and Modular Coil Design for the Chinese First Quasi-Axisymmetric Stellarator

Plasma and Fusion Research (2018)

Haifeng Liu A. Shimizu M. Isobe S. Okamura Shin Nishimura

The Chinese First Quasi-axisymmetric Stellarator (CFQS) is a joint project of international collaboration. It is designed and fabricated by Southwest Jiaotong University (SWJTU) in China and National Institute for Fusion Science (NIFS) in Japan. In this work, a plasma boundary and modular-coil system for the CFQS have been designed and optimized via scan of the magnetic configurations with various aspect ratios. The present target parameters of the CFQS are as follows: toroidal periodic number, aspect ratio, magnetic field strength and major radius are 2, 4.0, 1.0 T, and 1.0 m, respectively. The VMEC and NESCOIL codes are employed to obtain the optimum coil design via minimizing the normal component of the magnetic field on the target plasma boundary surface generated by the modular coils. In order to estimate the accuracy of the filament coils, the shape of the plasma boundary, rotational transform, depth of magnetic well and main Fourier components of magnetic field strength produced by the modular-coil system are compared with the target plasma boundary, rotational transform, depth of magnetic well and main Fourier components, correspondingly. This comparison between properties of the coil induced configuration and the target configuration shows a good agreement.

Fusion power

Aspect ratio (aeronautics)

10.1585/pfr.13.3405067

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Citations (51)

Preparation and characterization of polystyrene-based plastic scintillators as a self-vetoing structural material

Journal of Polymer Research (2025)

Y. L. Yan Yu Liu C. H. Fang J. J. Zhu Shin-Ted Lin

Polystyrene

Characterization

Expanded polystyrene

10.1007/s10965-024-04206-x

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Investigation of the edge ion-to-electron temperature ratio in the J-TEXT tokamak

Plasma Physics and Controlled Fusion (2021)

Hai Liu Kangzhong Xu Yuhong Xu Zhipeng Chen J. Cheng

Abstract The ion ( T i ) and electron ( T e ) temperatures at the last closed flux surface (LCFS) during density scanning discharges and in the scrape-off layer (SOL) with a constant plasma density have been measured in the J-TEXT tokamak using a retarding field analyzer and four-tip Langmuir probe, respectively. Both the LCFS T i and T e are found to reduce with increasing central line-averaged density ( n ˉ e ). The temperature ratio ( τ = T i / T e ) is about 2 for a low n ¯ e (1.5 → 2.5 × 10 19 m −3 ), decays in a moderate n ˉ e (2.5 → 3.5 × 10 19 m −3 ) and tends to unity at a high n ˉ e (3.5 → 4.2 × 10 19 m −3 ). This suggests that the ions and electrons at the LCFS (even in the SOL) are thermally decoupled at low or moderate n ˉ e and tend to full thermal coupling in the high-density plasmas. In addition, both T i and T e decrease with the radius and T e falls more steeply than T i due to faster parallel energy loss of electrons in the SOL. In contrast, τ rises with the radius, which indicates that the ions and electrons are much more thermally decoupled in the deeper SOL.

10.1088/1361-6587/abf85d

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Citations (2)

Anomalous Convection Reversal due to Turbulence Transition in Tokamak Plasmas

Chinese Physics Letters (2015)

Tiantian Sun Shaoyong Chen Zhanhui Wang Xiaodong Peng Jie Huang

A critical physical model, based on the ion temperature gradient (ITG) mode and the trapped electron mode (TEM), trying to explain the spatio-temporal dynamics of anomalous particle convection reversal (i.e., the particle convective flux reverses from inward to outward), is developed numerically. The dependence of density peaking and profile shape on the particle convection is studied. Only the inward pinch could lead to the increase of the density peaking. The validation of the critical model is also analyzed. A comparison of the estimates calculated by the model and the experimental results from the Tore Supra tokamak shows that they are qualitatively both consistent.

Particle (ecology)

Tore Supra

10.1088/0256-307x/32/3/035201

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Citations (5)

Focusing characteristics of the relativistic electron beam transmitting in ion channel

Plasma Science and Technology (2020)

Yuxi Xia Shengpeng Yang Shaoyong Chen Changjian Tang

Based on the beam–plasma system model established in this paper, the trajectory of the electron beam in the ion channel is studied quantitatively through the envelope equation. Under different initial system parameters, the focusing transmission conditions of the beam in the ion channel are discussed. Then, a series of particle-in-cell simulations are performed, which generally versifies the theoretical results and shows some further details of the focusing behavior of the beam. It is found that the deceleration of some electrons around the focusing point or the beam–plasma interaction at the ion channel boundary will result in the generation of the residual electrons, which forms the electron return current that leads to the new instabilities influencing the focusing characteristics of the beam.

Envelope (radar)

Relativistic electron beam

10.1088/2058-6272/ab785d

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Citations (3)

First-principles study on the mechanical properties and thermodynamic properties of Mo–Ta alloys

Plasma Science and Technology (2020)

Xin Zhang Heng Li Yuhong Xu Qi‐Jun Liu Yangyang Liu

10.1088/2058-6272/ab78bc

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Citations (7)