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物理学报 , 1993,
Abstract: By considering the lower hybrid wave trajectory,spectrum variation and power deposition in HT-6B tokamak plasma,we calculated the currents driven with different plasma density. The results show that there exists a density window for lower hybrid wave current drive (LHCD) ,i. e ,LHCD would be achieved only within a certain range of plasma density. The ex-planation of such a density window is given and the parameters option is also discussed.
Experimental characteristics of a lower hybrid wave multi-junction coupler in the HT-7 tokamak
Ding Bo-Jiang,Shan Jia-Fang,Liu Fu-Kun,Fang Yu-De,Wei Wei,Wu Zhen-Wei,Chen Zhong-Yong,Xu Han-Dong,Wang Mao,Jiang Min,Zhang Gong-Rang,Huang Feng,Zhao Yan-Ping,Kuang Guang-Li,HT- team,
,单家方,刘甫坤,方瑜德,韦 维,吴振伟,陈忠勇,徐汉东,王 茂,蒋 敏,张公让,黄 峰,赵燕平,匡光力,HT- team

中国物理 B , 2006,
Abstract: A phase-controlled lower hybrid wave (LHW) multi-junction (MJ) coupler (3(rows)×(columns)× (subwaveguides)) has been developed in the HT-7 tokamak. Simulations show that it is more effective for driving plasma current than an ordinary phase-controlled LHW antenna (3(rows)×12(columns)) (traditional coupler). The plasma--wave coupling experiments show that the reflection coefficient (RC) is below 10%, implying that the MJ grill can launch the wave into the plasma effectively. The effect of power spectrum launched by the MJ coupler on RC indicates that an optimal condition is requisite for a better coupling in the lower hybrid current drive (LHCD) experiments. Studies indicate that the drive efficiency of the MJ antenna is higher than that of the traditional one, which is mainly ascribed to the discrepancy in impurity concentration, plasma temperature, and spectrum directivity. An improved confinement with an electron internal transport barrier is obtained by LHCD. The analysis shows that the modified negative (low) magnetic shear and the change of radial electric field profile due to LHCD are possible factors responsible for the eITB formation.
Perpendicular momentum injection by lower hybrid wave in a tokamak  [PDF]
Jungpyo Lee,Felix I. Parra,Ron R. Parker,Paul T. Bonoli
Physics , 2012, DOI: 10.1088/0741-3335/54/12/125005
Abstract: The injection of lower hybrid waves for current drive into a tokamak affects the profile of intrinsic rotation. In this article, the momentum deposition by the lower hybrid wave on the electrons is studied. Due to the increase in the poloidal momentum of the wave as it propagates into the tokamak, the parallel momentum of the wave increases considerably. The change of the perpendicular momentum of the wave is such that the toroidal angular momentum of the wave is conserved. If the perpendicular momentum transfer via electron Landau damping is ignored, the transfer of the toroidal angular momentum to the plasma will be larger than the injected toroidal angular momentum. A proper quasilinear treatment proves that both perpendicular and parallel momentum are transferred to the electrons. The toroidal angular momentum of the electrons is then transferred to the ions via different mechanisms for the parallel and perpendicular momentum. The perpendicular momentum is transferred to ions through an outward radial electron pinch, while the parallel momentum is transferred through collisions.
Runaway electrons behaviors during ion cycolotron range of frequency and lower hybrid wave plasmas in the HT-7 Tokamak
HT-7 Tokamak离子回旋波和低杂波等离子体逃逸电子行为研究

Lu Hong-Wei,Hu Li-Qun,Zhou Rui-Jie,Xu Ping,Zhong Guo-Qiang,Lin Shi-Yao,Wang Shao-Feng,

物理学报 , 2010,
Abstract: HT-7 Tokamak is equipped with a lower hybrid wave (LHW) system and an ion cyclotron range of frequency (ICRF) system. ICRF can accelerate ions effectively, while LHW can accelerate electrons effectively. The generation of runaway electrons during the LHW and ICRF plasmas, as well as the time evolution of electron temperature during the ICRF and LHW plasmas was investigated in this paper. The runaway critical energy for runaway electrons was also calculated according to the experimental data. It was observed that the combination of ICRF and LHW can produce a higher heating efficiency and a better coupling between ICRF and plasmas if the power of LHW exceeds a critical value. Therefore, the generation of runaway electrons and fusion neutrons are affected by ICRF.


物理学报 , 1987,
Abstract: Nal(Tl) scintillation detector and Si(Au) surface barrier semiconductor detector are used to measure X-ray fluctuations in the HT-6B Tokamak device. The hard X-ray emission and sawtooth oscillations have been observed. The experiment shows hard X-ray fluctuations are due to MHD disturbances in the frequency range of 2-25 kHz.
Fast electron dynamics in lower hybrid current drive experiment on HT-7 tokamak

Shi Yue-Jiang,Wan Bao-Nian,Chen Zhong-Yong,Hu Li-Qun,Lin Shi-Yao,Ruan Huai-Lin,Qian Jin-Ping,Zhen Xiang-Jun,Ding Bo-Jiang,Kuang Guang-Li,Li Jian-Gang,HT- Team,

中国物理 B , 2005,
Abstract: Dynamic behaviour of fast electron in lower hybrid current drive (LHCD) experiment is a crucial issue in the sense of enhancing plasma performance. A new hard x-ray diagnostic system on HT-7 allows the investigation of the lower hybrid wave dynamics. The behaviour of fast electron is studied in several kinds of LHCD experiments, including long pulse discharges, high performance discharges and counter-LHCD experiments.
Suppression MHD instabilities by IBW heating in HT-7 Tokamak  [PDF]
C. M. Qin,Y. P. Zhao,X. J. Zhang,P. Xu,Y. Yang,the HT-7 team
Physics , 2010,
Abstract: In HT-7 tokamak, the m= 2/1 tearing mode can be effectively suppressed by the ion bernstein wave (IBW) when the location of power deposition is near the q=2 rational surface. Off-axis electron heating and greatly increase of electron density was observed, in the meantime, the particle confinement appears to be improved with the increased of the central line averaged electron density and the drop of Da emission. Induced large ne gradients and pressures were spatially correlated with the IBW deposition profile by theoretical calculation >. It is suggested that off-axis IBW heating modifies the electron pressure profile, and so the current density profile could be redistributed resulting in the suppression of the magnetohydrodynamics (MHD) instability. It provides an integrated way for making combined effects on both the stabilization of tearing modes and controlling of pressure profile.
AC operation and runaway electron behaviour in HT-7 tokamak

Lu Hong-Wei,Hu Li-Qun,Zhou Rui-Jie,Lin Shi-Yao,Zhong Guo-Qiang,Wang Shao-Feng,Chen Kai-Yun,Xu Ping,ZhangJi-Zong,Ling Bi-Li,Mao Song-Tao,DuanYan-Min,

中国物理 B , 2010,
Abstract: 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.
Experimental study of large power lower hybrid current drive on HT-7 tokamak

Xu Qiang,Gao Xiang,Shan Jia-Fang,Hu Li-Qun,Zhao Jun-Yu,

物理学报 , 2009,
Abstract: 在HT-7超导托卡马克成功进行了大功率(PLHW=100—800 kW,f=2.45 GHz)低混杂波电流驱动实验.研究了不同入射功率和等离子体密度下的低混杂波电流驱动效率.获得了以平均电子密度增加、氘阿尔法(Dα)线辐射减少为特征的粒子约束改善;粒子约束时间τp增加了约1.5倍.仔细研究了能量约束时间与等离子体密度和低混杂波功率的关系.


物理学报 , 2000,
Abstract: Quasi-steady-state H-mode has been achieved by combination of two lower hybrid w aves in HT-6M tokamak.Plasma energy confinement time increases by two times,and the particle confinement time increases by a factor of three under a high plasma density condition.The wave diffusion and current radial diffusion code is used to simulate the experimental data on HT-6M.The calculated results show that the off-axis power deposition of lower hybrid wave is formed due to the low toroidal magnetic field and high plasma density.Reversed sheared(RS) configuration of th e plasma current density is formed during H-mode phase.The RS configuration and internal transport barrier are attributed to the enhanced confinement improvemen t.The experimental data also gives the evidence for the reversed shear formation .
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