Table of Content

15 March 2010, Volume 30 Issue 1

Previous Issue    Next Issue

Plasma Physics

Study of SMBI fueling efficiency on HL-2A tokamak

CHEN Cheng-yuan, YAO Liang-hua, FENG Bei-bin, ZHOU Yan, YAN Long-wen

2010, 30(1):  1-6. 

Asbtract ( )   PDF (1674KB) ( )  

References | Related Articles | Metrics

The total particle increment in the plasma after SMBI could be calculated from the variation of the electron density profile detected by a multi-channel FIR HCN interferometer. At the divertor configuration and the limiter configuration，the SMBI fueling efficiencies on the high field side and the low field side are obtained first. The scope of the fueling efficiencies were consistent with those on Tore Supra.

Numerical investigation of effect of trapped electrons on current drive

YAO Kun, ZHAO Yan-ping, ZHANG Xin-jun

2010, 30(1):  7-11. 

Asbtract ( )   PDF (947KB) ( )  

References | Related Articles | Metrics

A 2-D Fokker-Planck equation in the effect of trapped electrons on current drive is revised with bounce average and solved by alternate direction implicit scheme. Effect of trapped electrons on current drive is calculated in different quasi-linear diffusion coefficients or different resonant regions. Numerical investigation shows that the effect of trapped electrons on current drive is negligible in plasma core. Effect of trapped electron on current drive is not improved well by enhancing diffusion coefficient or shifting resonant region.

Improved confinement and analyses of the net power input through the plasma edge on the HL-2A tokamak

GAO Jin-ming, LIU Yi, LI Wei, ZHOU Yan

2010, 30(1):  12-16. 

Asbtract ( )   PDF (1957KB) ( )  

References | Related Articles | Metrics

The phenomena of improved confinement has been observed with ECRH auxiliary heating under limiter discharge condition on the HL-2A tokamak, and electron line average density, plasma stored energy, radiated power within the separatrix, energy confinement time, H-alpha line emission etc. have been studied for the transition from L-mode to improved mode. At the same time, the time evolution of the profile of electron density and plasma radiation power have also been analyzed. Then several powers(auxiliary heating power, Ohmic heating power and the loss power) of correlating improved confinement are analyzed, and the dependence of the net power that flows through the edge of the plasma for the improved confinement transition on electron line average density and toroidal magnetic field has been carefully studied.

Role of viscosity induced polarization current in micro-island evolution

CAO Jin-jia, WANG Ai-ke, SUN Ai-ping

2010, 30(1):  17-20. 

Asbtract ( )   PDF (467KB) ( )  

References | Related Articles | Metrics

The perpendicular viscosity for the micro-island (w/p_i→0) has been derived. Based on the viscosity, the electrostatic potential function and the dynamic equation of magnetic island evolution have been obtained. The dynamic equation indicates that the viscosity-induced polarization current plays an unstable role in micro-island evolution. Furthermore, numerical analyses show that when ion temperature is small or decreases suddenly, the polarization current makes micro-islands grow rapidly, which are roughly in agreement with the experimental observation.

Influence of incident wave power density on electron cyclotron current drive

PENG Xiao-wei1, GONG Xue-yu1, LIU Wen-yan1, GAO Jin-sheng2, LIU Yan1, HUANG Qian

2010, 30(1):  21-24. 

Asbtract ( )   PDF (743KB) ( )  

References | Related Articles | Metrics

In the condition of reactor scale plasma, the influence of incident wave power density on electron cyclotron current drive and power deposition is studied with the relativistic Fokker-Planck equation incorporated into a beam-tracing code. The results show that current drive efficiency is reduced slightly, power deposition profile is broaden and move towards the edge plasma a little, due to the high power density wave beam.

Ions acceleration in plasma under Compton scattering

HAO Xiao-fei1, WANG Qi-hua2，HAO Dong-shan1

2010, 30(1):  25-29. 

Asbtract ( )   PDF (1036KB) ( )  

References | Related Articles | Metrics

Using the nonlinear Compton scattering model between an electron and a multi-photon group and a new ion propagation mechanism formed by the incident and scattered beams, the movement of the ions in the plasma of the high power multi-beams coherent coupling laser was studied and the dynamics equation was given out, numerical analogue to the equation was conducted. The result shows that the optical propagation velocity is decreased and the vector and scalar potentials of the system are increased by the scattering. The proton can be accelerated to 5.40GeV energy by the coherent coupling laser beams formed by the incident and scattered optical beams，and the coupling electric field along the propagation direction takes a key effect.

Numerical calculation of radiation pattern of plasma channel antenna

XIA Xin-ren, YIN Cheng-you

2010, 30(1):  30-36. 

Asbtract ( )   PDF (1880KB) ( )  

References | Related Articles | Metrics

The idea of plasma channel antenna (PCA) for high power microwave weapon is presented in this paper. The radiation pattern of PCA is calculated. The directivity functions of general antenna are derived. The near electromagnetic model of PCA is created based on physical circumstances. The electromagnetic fields of PCA and surrounding air in cylindrical coordinate are given. The dispersion equation of PCA is deduced by applying the boundary conditions of electromagnetic fields. The surface wave vector of PCA is achieved. The variations of radiation characteristic with plasma density, antenna length and antenna radius are emphatically discussed. The controllability of PCA’s radiation patterns is confirmed.

Prediction of plasma disruption using artificial neural network on HL-2A

MA Rui, WANG Ai-ke, WANG Hao

2010, 30(1):  37-41. 

Asbtract ( )   PDF (960KB) ( )  

References | Related Articles | Metrics

Prediction of plasma disruption using artificial neural networks (ANN) has been investigated on HL-2A. Two methods have been adopted to train ANN. In the first one, the original experimental data are used directly as the ANN input. In the second one, in order to reduce the noise and enlarge the implicit disruption information in original Mirnov signal, the preprocessing is given in original Mirnov signal in the training subset. The prediction results indicate that the second method is more accurate and effective comparing with the first one.

Nuclear Fusion Engineering and Technology

Transmission characteristic measurement and analysis of LHCD on HL-2A

BAI Xing-yu, ZENG Hao, RAO Jun

2010, 30(1):  42-45. 

Asbtract ( )   PDF (622KB) ( )  

References | Related Articles | Metrics

The HL-2A LHCD transmission characteristic measurement with low power and high power were respectively carried out in 2006 and 2008. The result is shown as follows: the transmission rate was 94.05% and the maximum phase difference between the four spur tracks was 11.09° at the low power, the transmission rate was 76%~95% at the high power. In addition, the transmission rate decreased obviously with power when the total power increased up to 230kW.

Improvement of Gaussian antenna for electron cyclotron emission radiometer on HT-7 tokamak

FEI Qin-shan, LING Bi-li, TI Ang, LIU Yong, XIONG Gang,ZHANG Li-li, LI Er-zhong,

2010, 30(1):  46-50. 

Asbtract ( )   PDF (867KB) ( )  

References | Related Articles | Metrics

A scheme for redesigning its antenna in Gaussian optics is presented for improving the poloidal spatial resolution of the plasma electron cyclotron emission (ECE) super-heterodyne radiometer diagnostic system on the HT-7 tokamak. It is shown that the Gaussian optic loss of the radiant energy from the plasma ECE is no more than 13% by optimizing the dimensions of the circular pyramidal horn，the focus of the convex lens of the antenna system and their relative positions when the Gaussian bean radius of the emission of the ECE novel second harmonic is only 30mm or so.

Development of DSP control system on 3-phase AC/AC cycloconverter without circulating current

PENG Jian-fei, XU Li-rong , Li Hua-jun, XUAN Wei-min, WANG Shu-jin

2010, 30(1):  51-55. 

Asbtract ( )   PDF (2854KB) ( )  

References | Related Articles | Metrics

A DSP-based control system on a three-phase AC/AC cycloconverter without circulating current, including its hardware and software, has been developed. The results from the trial run are introduced in this paper. They show that the developed DSP-based control system has excellent control characters in both precision and real time. 0~15Hz current and voltage can be output by the cycloconverter, and the current dead-band can be reduced to 1.2ms.

Coupling properties of EAST lower hybrid wave launcher

LI Jun, JIA Hua, LIU Fu-kun

2010, 30(1):  56-59. 

Asbtract ( )   PDF (1519KB) ( )  

References | Related Articles | Metrics

The coupling properties of EAST LHW launcher are analyzed by numerical simulation. Based on the two-dimensional linear coupling theory, the relationships of power reflection coefficient and power directivity with plasma parameters are calculated. The effects of passive waveguides on the coupling properties are analyzed, and the power spectrums of launcher under different parameters are given. The results indicate that the passive waveguides give a slight reduction on power directivity, but to decrease the power reflection coefficient, which is good for the coupling between launcher and plasma.

Numerical analysis on coupling properties of the LHCD multijunction launcher

JIA Hua, QIN Yong-liang, LIU Fu-kun, KUANG Guang-li

2010, 30(1):  60-66. 

Asbtract ( )   PDF (1645KB) ( )  

References | Related Articles | Metrics

The coupling properties of the Lower Hybrid Current Drive (LHCD) multijunction (MJ) launcher are investigated numerically. The Airy function is used to calculate the plasma impedance and the grill-plasma scattering matrix is deduced, then the coupling properties of the HT-7 LHCD MJ launcher are studied with the antenna scattering matrix and the grill-plasma scattering matrix based on the liner coupling theory. The average power reflection coefficient, directivity, power spectrum are obtained for different edge plasma densities and for different phasings between main waveguides. The results show that the power reflection coefficient of the MJ launcher is much lower and less sensitive to the phase difference than that of the conventional grill because of its self-matching characteristic. However, due to the excrescent side lobe, the current drive efficiency is lower.

Study on 1.5MW RF amplifier for EAST ICRF heating system

CHEN Gen, MAO Yu-zhou, ZHAO Yan-ping

2010, 30(1):  67-70. 

Asbtract ( )   PDF (1597KB) ( )  

References | Related Articles | Metrics

Preparations for the final power amplifier of the 1.5MW RF source were discussed in the EAST ICRF heating system with a wide frequency range of 25 to 70MHz. The wide-band, high-power, steady-state RF amplifier will be illustrated from three main aspects: the optimized operating parameters, input circuit, and output circuit. The analysis of this amplifier is in agreement with test results. It could be a foundation for the reliable operation of ICRF heating system.

Helium experiment loop of CH HCSB TBM

XIANG Bin1, 2, FENG Kai-ming1, YE Xing-fu1, QIU Sui-zheng2

2010, 30(1):  71-75. 

Asbtract ( )   PDF (1197KB) ( )  

References | Related Articles | Metrics

Main requirements, characteristics and the component equipments parameters of the constructing high-temperature and high-pressure helium experiment loop are presented. Thermal-hydraulics design and analysis have been investigated by RELAP 5 code, and pipe optimization, equipments layout and stress analyses have been finished by CAESAR code. The results show that the engineering design of the experimental loop is feasible.

Design of tube penetration structure for ITER gas injection system

JIANG Tao, LI Bo, LI Wei, WANG Ming-xu

2010, 30(1):  76-81. 

Asbtract ( )   PDF (1534KB) ( )  

References | Related Articles | Metrics

The design of the tube penetration structure which is one of the important structure in the GIS/GDC system was conducted. The detailed design and preliminary results of divertor port extension and cryostat penetration structure, and of upper port extension and torus vacuum closure flange penetration structure were given.

Alignment of EAST in-vessel components

LIU Xu-feng, WEI Jing, ZHENG Fu-bin, CHEN Wen-ge, ZHOU Zi-bo, YAO Da-mao

2010, 30(1):  82-85. 

Asbtract ( )   PDF (1368KB) ( )  

References | Related Articles | Metrics

Optical instruments integrating with machine template is used to align the assembly of EAST in-vessel components. The measure benchmarks of in-vessel components are introduced by the benchmark holes on the template. The final aspect of the first wall is calibrated to the accurate position by another special template.

Non-Fusion Plasma Applications

The effect of plasma sheath and collision on microwave resonator probe diagnosing

HUANG Yong, SHI Jia-ming, YUAN Zhong-cai, XU Ji-wei

2010, 30(1):  86-89. 

Asbtract ( )   PDF (732KB) ( )  

References | Related Articles | Metrics

The effects of plasma sheath and collisions become significant in the density measurement of gas discharges at pressures greater than 133Pa. The probe model correction is performed, and the plasma sheath and collision correction factors are deduced. The effect of probe dimentions on demsity measurement is esplosed. It reveals that choosing a proper larger probe width will be beneficial to minimizing the measure error, and the most favorable value of probe radius is 0.2mm.

Analysis of power deposition on Langmuir probe for high current ion source

XIE Ya-hong, HU Chun-dong, LIU Sheng, LIU Zhi-min

2010, 30(1):  90-93. 

Asbtract ( )   PDF (529KB) ( )  

References | Related Articles | Metrics

The density of power deposition of the Langmuir probe in the plasma measuement is analyzed, the temperature rise of the probe is calculated preliminarily, and guidance for the probe diagnostic in high current ion source is provided.

A simple method for plasma diagnosis in glow discharge

SUN Feng-lou, LU Jun-jie

2010, 30(1):  94-96. 

Asbtract ( )   PDF (320KB) ( )  

References | Related Articles | Metrics

Considering the collision as energy transfer mechanism, and the approximate condition of local thermodynamic equilibrium, and the potential distribution between two electrodes in glow discharge, relations for electron density with macro parameters pressure and electron temperature with electric field strength are obtained. A diagnostic method for measuring the electron temperature and electron density using pressure and applied voltage and current is presented. The obtained results are verified by using Langmuir probe.