Loading...
Welcome to Nuclear Fusion and Plasma Physics, Today is Share:

Table of Content

    15 December 2016, Volume 36 Issue 4
    Plasma Physics
    Development of a fast sweeping Q-band microwave reflectometer on HL-2A tokamak
    ZHANG Bo-yu1, SHI Zhong-bing1, ZHONG Wu-lu1, YANG Zeng-chen1, 2, SHI Pei-wan1,JIANG Min1, LIU Ze-tian1, DING Xuan-tong1, YANG Qing-wei1
    2016, 36(4):  289-296.  DOI: 10.16568/j.0254-6086.201604001
    Asbtract ( )   PDF (5651KB) ( )  
    References | Related Articles | Metrics

    The fast sweeping frequency modulated continuous wave (FMCW) reflectometer was developed on the HL-2A tokamak to measure the electron density profile with high temporal and spatial resolutions. A wide band voltage controlled oscillator (VCO) is used as a local oscillator, which is driven by an arbitrary waveform generator (AWG). The launching frequency covers Q band (33~50GHz) and the temporal resolution can reach about 6μs. Dynamic calibration technique of VCO is developed and the difference between static and dynamic responses of VCO is obtained. To acquire constant beat frequency when fixed reflector, nonlinear response of source and dispersion of waveguide are taken into account, making it easy to reduce noise and process data. A direct phase extracting technique is introduced to achieve rapid density profile inversion. With the reflectometer system, the density profiles at L-mode and H-mode have been observed, and the evolution of pedestal during ELM is demonstrated.

    Data processing of Langmuir probe based on improved wavelet denoising method
    TONG Wei-ming, LI Peng, TAO Bao-quan, JIN Xian-ji
    2016, 36(4):  297-302.  DOI: 10.16568/j.0254-6086.201604002
    Asbtract ( )   PDF (1024KB) ( )  
    References | Related Articles | Metrics

    An improved threshold function is proposed with the characteristics analysis of soft and hard threshold denoising methods. Based on the characteristics of I-V curve of Langmuir probe, an improved standard deviation estimating method is introduced to calculate the wavelet threshold. Denoisng the characteristic curve with improved threshold function and threshold, and the simulation results show that, the improved denoising method preformed well, the signal noise ratio is improved and the root mean square error is reduced. The denosing effectiveness is better than traditional threshold method.

    Study of runaway electrons synchrotron radiation on EAST tokamak
    YANG Zhen-dong1, 2, FANG Jian-an1, GONG Xian-zu2, GAN Kai-fu2, CUI Zhi-xue1
    2016, 36(4):  303-308.  DOI: 10.16568/j.0254-6086.201604003
    Asbtract ( )   PDF (8211KB) ( )  
    References | Related Articles | Metrics

    The infrared and visible image from synchrotron radiation emitted by the runaway electrons (Res) in EAST tokamak is observed by using the infrared (IR) camera and visible camera. The relation between the wavelength of the synchrotron radiation emitted by runaway electrons (RE) and the energy of the RE is studied. The result shows that the wavelength of the synchrotron radiation emitted by the RE with lower energy RE is in the infrared wavelength range. As the energy of RE increases, the wavelength of the synchrotron radiation emitted by the RE will shift to the side of short waves, which then could be detected by a visible camera. The RE behaviors under the influence of the hybrid waves (LHWs) and neutral beam injection (NBI) are also investigated. It is found that the fast electrons excited by LHWs can be accelerated to runaway electrons during the initial phase of the LHWs injection.

    Direct numerical simulations of magnetohydrodynamics on turbulent duct flow
    TAN Zhong-quan1, MAO Jie1, LIU Ke2
    2016, 36(4):  309-314.  DOI: 10.16568/j.0254-6086.201604004
    Asbtract ( )   PDF (9488KB) ( )  
    References | Related Articles | Metrics

    Magnetohydrodynamic turbulent flow solver with low magnetic Reynolds number was developed in open source CFD software toolbox of OpenFOAM. Hydrodynamic turbulent flow and magnetohydrodynamic turbulent flow in a 2π ×1×1 square duct were simulated by the validated turbulent DNS solver. The distribution of instantaneous velocity, average velocity on the cross section, the root mean square value of the fluctuation velocity and the turbulent kinetic energy along bisector of the cross section were presented. The numerical results show that the applied external magnetic field has a suppression effect on MHD turbulent fluctuation. At the same time, the suppression effect is anisotropic.

    Dust-acoustic shock waves in strongly coupled dusty plasmas with charge fluctuating positive dust
    CHEN Hui, ZHONG Qing-lin, LIU San-qiu
    2016, 36(4):  315-321.  DOI: 10.16568/j.0254-6086.201604005
    Asbtract ( )   PDF (824KB) ( )  
    References | Related Articles | Metrics

    The linear dispersion relation of the dust acoustic wave (DAW) and nonlinear propagation of the dust acoustic solitary waves (DASWs) in the strongly coupled dusty plasma are studied. Under the conditions that a fully ionized three-component model plasma containing electrons, ions, and charge fluctuating positive massive dust grains is considered, and electrons and ions are assumed to obey the Boltzmann density distribution while the inertial dust component is described by a group of classical fluid equations, a linear dispersion relation of DAW is obtained by linearizing the equations of system, and it shown that the dispersion relation of DAW is much influenced by the ion concentration parameter. The Burgers equation describing small amplitude solitary waves is obtained by using the reductive perturbation method. Based on the Burgers equation, the basic features of the DASWs are researched, it shown that the DASW is much modified by the strongly couple effects of the dust grains. The research results may be helpful to understand the properties of localized waves in space dusty plasma.

    A semi-empirical conductivity model for dense plasma
    WANG Kun1, 2, SHI Zong-qian1
    2016, 36(4):  322-327.  DOI: 10.16568/j.0254-6086.201604006
    Asbtract ( )   PDF (1435KB) ( )  
    References | Related Articles | Metrics

    The transition of ionization mechanism from thermal ionization to pressure ionization can be described with Saha equation which is modified by the combination of pressure ionization theory and Debye theory. The results of Saha equation with combination of pressure ionization and Debye theory corrections are compared with that for different ionization models. The fully ionized plasma model is adopted to calculate the electron relaxation time in the region of ionized gases. The electron relaxation time is calculated according to the mean free path of the electrons in the region of condensed matter. A formula is constructed to make a smooth blending of the conductivity between the different regions. Therefore, a wide range semi-empirical conductivity model which is valid from ideal plasma to condensed matter is established. The conductivity data derived from the semi-empirical model is compared with experimental data.

    Nuclear Fusion Engineering and Technology
    Preliminary accident analysis for CN HCCB TBS heat exchanger tube rupture
    WANG Yan-ling, ZHANG Long, YE Xing-fu, WANG Xiao-yong
    2016, 36(4):  328-333.  DOI: 10.16568/j.0254-6086.201604007
    Asbtract ( )   PDF (2784KB) ( )  
    References | Related Articles | Metrics

    Compared with CCWS-1, the detailed analysis for heat exchanger tube rupture accident of CN HCCB TBS using RELAP software is provided. The two system are simplified rationally, the relevant RELAP joint drawing is given, and the influence of different break point accidents on the CN HCCB TBS and ITER CCWS-1 are analyzed. Analysis results show that a similar shocking wave will spread from the break point towards both sides of the water pipes. And the helium released into the water will accumulate in the high points of CCWS-1, so reasonable exhaust path at the high points needs to be considered In addition, in order to limit the amount of helium accessing into CCWS-1, the isolation valves located on the waterside of heat exchanger need to be installed. The isolation valves must ensure high reliability and short response time.

    Magnetizing test for stator core of 300MVA pulse generator
    WANG Hai-bing, PENG Jian-fei, XUAN Wei-ming, LI Hua-jun, WANG Xiao-ping, LI Zhi-jian
    2016, 36(4):  334-337.  DOI: 0254-6086(2016)04-0334-04
    Asbtract ( )   PDF (1702KB) ( )  
    References | Related Articles | Metrics

    In order to check if there is iron core lamination short out and the bolt are clamped, stator core magnetizing test of generator is needed after completed generator stator iron lamination and impaction in the site. Alternating current flow into the field winding twined on the stator core, the core loss is generated in the core and the core is heated. By measuring the temperature rise of the various parts of the core, it is estimated that whether the core is qualified based on the test standard. Due to the working frequency of 300MVA pulse generator is changing but not constant 50Hz power frequency, thus the unit iron loss of stator core of variable frequency of 67Hz and 99.6Hz is obtained through calculation. The stator core magnetizing test results of pulsed generator show that the stator core installation quality and insulation are qualified. The test results provide reference for stator core magnetization test of the variable frequency generator.

    Development and preliminary experiments of high power RF ion source
    GU Yu-ming, HU Chun-dong, XIE Ya-hong, XIE Yuan-lai, LI Jun, LIANG li-zheng,CHEN Yu-qian
    2016, 36(4):  338-343.  DOI: 10.16568/j.0254-6086.201604009
    Asbtract ( )   PDF (5811KB) ( )  
    References | Related Articles | Metrics

    The structure design of RF ion source driving source and the heat flow and solid coupling analysis of RF coils were introduced. RF ion source is produced by the external antenna inductive coupling. Using design of dual RF driving source, each RF driving source power is about 60kW, and the total RF ion source power is 120kW, which can produce uniform high-density plasma to meet the stability requirements of long pulse operation. Upon completion of the above work, the RF ion source prototype assembly and preliminary test were completed.

    Parameter design and estimation of electrical deflection system for neutral beam injector
    LIANG LI-zhen, ZHAO Xiang-xue, WANG Yan, HU Chun-dong
    2016, 36(4):  344-348.  DOI: 10.16568/j.0254-6086.201604010
    Asbtract ( )   PDF (379KB) ( )  
    References | Related Articles | Metrics

    A set of electric deflection structure for EAST neutral beam injector was designed, and the core parameters of the system were estimated. The electric deflection system can meet the requirement of 80keV deuterium ion beam deflection under deflection field formed by 4.41kV deflection voltage. In the deflection field modulation, the electric deflection system can effectively reduce the heat load of the ion dump. Thus, it is very easy to meet the need of steady state operation for EAST neutral beam injector.

    Temperature and stress fields in TIG welding for medium thickness plate of RAFMs
    YAO Jin-jian1, LIU Su-mei1, 2, LU Min-xuan2, LEI Ming-zhun2, PEI Kun2
    2016, 36(4):  349-354.  DOI: 10.16568/j.0254-6086.201604011
    Asbtract ( )   PDF (5172KB) ( )  
    References | Related Articles | Metrics

    Some simulations and experiments about welding processes of the reduced activation martensitic/ferritic steel (RAFMs) were done respectively in this paper. The multi-welding processes for medium thickness plate of RAFM steel were simulated in three-dimensional finite element models by ANSYS software. The temperature fields and stress fields from simulation were contrasted with that from experiments respectively, and the heat affected zones of welding were calculated and checked. Meanwhile, the metallic texture graphic analysis and hardness tests for welded zones were performed. The results from both are very similar, and the fused metal welding zones are very well without obvious defects by used 316L welding padding. The hardness on welding zone is much higher than the heat-affected zone, also base materials.

    Research and experiment of liquid lithium loop
    XUE Xiao-yan1, ZHANG Wei-wei1, ZUO Hao-yi1,OU Wei2,CAO Xiao-gang2, YANG Dang-xiao1,CHEN Shun-li2, GOU Fu-jun2
    2016, 36(4):  355-361.  DOI: 10.16568/j.0254-6086.201604012
    Asbtract ( )   PDF (12285KB) ( )  
    References | Related Articles | Metrics

    The study status of flowing liquid lithium loop in Sichuan University is introduced mainly, which is based on reviewing study of lithium loops at home and abroad in the paper. The loop is designed to study the interaction of plasma with free flowing liquid lithium surface. The aims are summarized as follows: (1) to obtain the free flowing liquid lithium surface with stability and uniformity; (2) to understand the physical evaporation and sputtering of lithium during plasma irradiation, and the retention of hydrogen, its isotopes and helium; (3) to study the compatibility of structural materials in liquid lithium under the plasma irradiation. The device includes the liquid lithium circulating part and linear high density plasma generator.

    Status and strategy on standardization of China’s procurement packages for ITER project
    LI Guo-qing1, WANG Min2, WU Shu-qin2, LIU Li-po1, JIN Li-qiang1
    2016, 36(4):  362-367.  DOI: 10.16568/j.0254-6086.201604013
    Asbtract ( )   PDF (1063KB) ( )  
    References | Related Articles | Metrics

    The information of China's procurement packages for ITER project is introduced briefly. The principles of adopting industry codes and standards in ITER Project and the features of adopting industry codes and standards for China's procurement packages are analyzed. The statuses of standardization on China's procurement packages are also summarized. Based on requirements of codes and standards for procurement packages in ITER project currently and future needs of codes and standards in the field of magnetic confinement fusion in China, the strategies on standardization for China's procurement packages are also presented.

    Non-Fusion Plasma Applications
    Effect of plasma on low pressure supersonic helium flow field
    HUAI Ying1, LI Shou-zhe2, WU Ke-nan1, YE Fu-li2
    2016, 36(4):  368-373.  DOI: 10.16568/j.0254-6086.201604014
    Asbtract ( )   PDF (2895KB) ( )  
    References | Related Articles | Metrics

    Influence of a boundary surface discharge plasma on the low-pressure supersonic helium flow field is investigated with a DC-driven discharge plasma actuator and its effect on altering the gas flow field by means of the molecular tagging smoke wire. It is found that the cathode region of the boundary surface discharge plasma plays a pivotal role on the control of supersonic flow of helium on the actual conditions. In addition, the higher the driven voltage of plasma actuator, the better the control of airflow field. With the increase of the driven voltage, the discharge area on cathode region will be enlarged, correspondingly the actual working area is enlarged, so that the controlling effect on airflow field is more appreciable.

    Polar mesosphere layered structure based on dusty plasma theory
    JIANG Lin, SHI Yan-xiang
    2016, 36(4):  374-378.  DOI: 10.16568/j.0254-6086.201604015
    Asbtract ( )   PDF (1066KB) ( )  
    References | Related Articles | Metrics

    Taking into account the processes of charging and discharging of dust particles, the influence of dust ice particles bite-outs on polar mesosphere electron density layered structure and the conductivity and dielectric coefficient based on the dusty plasma theory is studied. It is shown that the electron density layered structure in polar mesosphere 80-90 km is caused by the dust ice particles bite-outs, which lead to the appearance of dusty plasma dielectric coefficient and conductivity layered structure along the height between 80 and 90km. The reference for explaining and researching on polar mesosphere summer echoes phenomenon were provided.