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1.
在HT-7托卡马克上,只在等离子体放电击穿阶段充气,击穿后关闭充气阀门,让装置内真空室器壁的出气维持放电的进行,通过密度衰减实现了slide-away放电.实验分析了不同等离子体电流平台下的slide-away放电模式的密度阈值,以及相同充气量的条件下放电等离子体电流对实现slide-away放电的影响.研究了slide-away放电模式下密度提升对等离子体放电状态的影响.结果发现,slide-away放电模式下的密度提升使得Ha线辐射强度增强,等离子体中超热电子的约束性能变差,等离子体芯部的超热电子减少,高能逃逸电子厚靶轫致辐射增加.
关键词:
slide-away放电
托卡马克
等离子体
逃逸电子 相似文献
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A. Ti B. L. Ling Q. S. Fei X. Gao 《International Journal of Infrared and Millimeter Waves》2007,28(3):243-249
The incoherent radiation emanating out of the tokamak plasmas gives vital information about the electron temperature. Electron
cyclotron emission (ECE) is a powerful diagnostic tool for the measurement of electron temperature due to many advantages
such as the high spatial and temporal resolutions. This paper presents the sixteen channel superheterodyne radiometer as an
electron cyclotron emission diagnostic to measure the electron temperature on HT-7 tokamak. 相似文献
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Electron temperature fluctuation in the HT-7 Tokamak plasma observed by electron cyclotron emission imaging
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The fluctuation of the electron temperature has been measured by
using the electron cyclotron emission imaging in the Hefei Tokamak-7
(HT-7) plasma. The electron temperature fluctuation with a broadband
spectrum shows that it propagates in the electron diamagnetic drift
direction, and the mean poloidal wave-number $\bar{k}_{\theta}$is
calculated to be about 1.58 cm-1, or
\bar{k}θ ρs≈ 0.34. It indicates that the
fluctuation should come from the electron drift wave turbulence. The
linear global scaling of the electron temperature fluctuation with
the gradient of electron temperature is consistent with the mixing
length scale qualitatively. Evolution of spectrum of the fluctuation
during the sawtooth oscillation phases is investigated, and the
fluctuation is found to increase with the gradient of electron
temperature increasing during most phases of the sawtooth
oscillation. The results indicate that the electron temperature
gradient is probably the driver of the fluctuation enhancement. The
steady heat flux driven by electron temperature fluctuation is
estimated and compared with the results from power balance
estimation. 相似文献
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Xiaofeng Han Xiang Gao Yinxian Jie Junyu Zhao Qing Zang Wei Gao 《Physics letters. A》2010,374(45):4602-4606
The particle transport coefficients were investigated in ac plasmas by density modulation method on HT-7 tokamak. It is observed that the particle diffusion coefficient (D) is almost the same in various cases and varies with the electron density. The convection velocity (V) is equal to the value of inward pinch velocity (VE×B) for low and high density discharges. The particle confinement time becomes much higher when the directions of plasma current and toroidal field are uniform. 相似文献
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Identification of m=2 competent mode of complex magneto-hydro-dynamics activities during internal soft disruption based on singular value decomposition and tomography of soft-X-ray emission on the HT-7 tokamak
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In this paper,the singular value decomposition(SVD) method as a filter is applied before the tomographic inversion of soft-X-ray emission.Series of ’filtered’ signals including specific chronos and topos are obtained.(Here,chronos and topos are the decomposed spatial vectors and the decomposed temporal vectors,respectively).Given specific magnetic flux function with coupling m = 1 and m = 2 modes,the line-integrated soft-X-ray signals at all chords have been obtained.Then m = 1 and m = 2 modes have been identified by tomography of simulated ’filtered’ signals extracted by the SVD method.Finaly,using the experimental line-integrated soft-X-ray signals,m = 2 competent mode of complex magnetohydrodynamics(MHD) activities during internal soft disruption is observed.This result demonstrates that m = 2 mode plays an important role in internal disruption(Here,m is the poloidal mode number). 相似文献
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受控热核聚变研究在发展了50年后,在2003年进入了一个新的阶段,国际热核聚变实验堆项目将最后选址开工。科学工作者们希望这个在新世纪初开始的项目能成为彻底解决能源问题的发端,中国科学院等离子体物理研究所最近在受控热核聚变科研上取得了长足进展,朝着稳态高温等离子体的方向又跨出了坚实的一步.其HT-7超导托卡马克高温等离子体的持续时间达到63.95s,成为目前世界上能开展分钟级高温等离子体放电的仅有的两个超导托卡马克装置之一。文章主要介绍了中国科学院等离子体物理研究所最新的聚变实验研究进展。 相似文献
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Measurement of the line shape of optically thick and optically thin lines in the electron cyclotron radiation spectrum emitted by a tokamak plasma may yield both electron temperature and density profiles. Currently temperature profiles are routinely extracted from optically thick lines. Consequently, this paper is addressed to the density profile problem. Algorithms for extracting density profiles are outlined in the case of uncontrolled reflection and controlled reflection of the cyclotron radiation within the tokamak vacuum chamber. 相似文献
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Operation of HT-7 tokamak in a multicycle alternating
square wave plasma current regime is reported. A set of AC operation
experiments, including LHW heating to enhance plasma ionization
during the current transition and current sustainment, is described.
The behaviour of runaway electrons is analysed by four HXR detectors
tangentially viewing the plasma in the equatorial plane, within
energy ranges 0.3--1.2~MeV and 0.3--7~MeV, separately. High energy
runaway electrons (\sim MeV) are found to circulate predominantly
in the opposite direction to the plasma current, while the number of
low energy runaway electrons (\sim tens to hundreds of keV)
circulating along the plasma current is comparable to that in the
direction opposite to the plasma current. AC operation with lower
hybrid current drive (LHCD) is observed to have an additional
benefit of suppressing the runaway electrons if the drop of the loop
voltage is large enough. 相似文献
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A Fokker-Planck study is carried out for tokamak electron cyclotron resonance heating by writing the quasi-linear diffusion operator into a form adaptive to the collision operator and considering the wave absorption characteristics of both the O-mode and the X-mode in different magnetic surfaces. Though the Fokker-Planck code is non-relativistic in nature, however, if the relativistic resonance condition for the nearly perpendicularly propagating waves is treated suitably, we can obtain correct results. The energy loss mechanism through anomalous transport is also modelled using a suitable loss term. In the heating phase, the electron distribution deviates from the Maxwellian distribution substantially, which leads to non-linear absorption characteristics. The wave damping rate is non-linear and changes with time. The electron pressure is usually anisotropic under different conditions: p_{e⊥}/p_{e‖}>2 for different D_0 and τ_e. 相似文献
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为了检测到散射信号且有较高的信噪比,使用硅雪崩二极管(APD)探测器探测汤姆逊散射光,采用电荷敏感运算放大器减小电子噪声。同时,设计了放大电路,并采取了一些抗干扰措施。在实验中,此激光汤姆逊散射系统成功地测量出HT-7等离子体的电子温度。 相似文献
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在HT-7装置上建立了一套高速CCD可见光成像诊断,测量了边界等离子体的可见光辐射成像.在HT-7装置放电中,首次观察到在等离子体边界区域存在一条极向旋转的可见光辐射带,由CCD诊断系统得到其极向旋转的频率为858Hz.根据多道Hα阵列测量得到极向旋转频率为952Hz.多道磁探针信号测量发现,等离子体内部存在m/n=3/1的电磁模,该模的旋转频率为972Hz.从电子回旋辐射诊断系统得到的电子温度剖面发现该模的磁岛宽度约为2.5cm. 相似文献
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The line-integrated optical measurement of impurity radiation profiles for the study of light impurity transport is performed in the HT-7 tokamak. The carbon impurity line emissivity is obtained by Abel inversion. The radial transport behaviours of carbon impurities at different central line averaged electron densities ne are investigated in ohmic discharges. The diffusion coefficient Dk(r), the convection velocity Wk(r) and the total flux of the impurity ions Fk decrease with the increase of ne, which shows a reduction in the impurity particle transport at higher electron densities. 相似文献
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在HT-7装置上建立了一套高速CCD可见光成像诊断,测量了边界等离子体的可见光辐射成像。在HT-7装置放电中,首次观察到在等离子体边界区域存在一条极向旋转的可见光辐射带,由CCD诊断系统得到其极向旋转的频率为858Hz。根据多道Hα阵列测量得到极向旋转频率为952Hz。多道磁探针信号测量发现,等离子体内部存在m/n=3/1的电磁模,该模的旋转频率为972Hz。从电子回旋辐射诊断系统得到的电子温度剖面发现该模的磁岛宽度约为2.5cm。 相似文献
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