Ramp-up experiments by means of lower hybrid wave on HT-7 superconducting tokamak have been performed and analyzed. A ramp-up rate of over 300 kA/s is obtained and a conversion efficiency of over 1.0% has been achieve...Ramp-up experiments by means of lower hybrid wave on HT-7 superconducting tokamak have been performed and analyzed. A ramp-up rate of over 300 kA/s is obtained and a conversion efficiency of over 1.0% has been achieved during the ramp-up phase. The study of the dependence of conversion efficiency on plasma density shows that the conversion efficiency is affected by the driven current, which is mainly dominated by the competition of impurity concentration with wave accessibility condition. In addition, the effect of current profile may play an important role in determining the conversion efficiency.展开更多
Lower hybrid current drive experiments on the HT-7 device have been carried out by scanning the following parameters: central line averaged electron density (ne = 0.6 - 2.0 × 1019m-3) and toroidal magnetic field ...Lower hybrid current drive experiments on the HT-7 device have been carried out by scanning the following parameters: central line averaged electron density (ne = 0.6 - 2.0 × 1019m-3) and toroidal magnetic field (Bt = 1.62 - 2.0 T). The dependence of current drive efficiency on these parameters has been studied and the experimental curves of current drive efficiency as a function of ne and Bt have also been obtained. From these experimental results, it can be seen that current drive efficiency rises with the increase of toroidal magnetic field. As plasma density increases, the current drive efficiency first increases to a certain value, then gradually decreases, that is, there exists an optimized density regime where a better drive efficiency can be obtained. The analysis shows that the current drive efficiency is mainly affected by wave accessibility and impurity concentration, and the competition of these two factors determines the current drive efficiency.展开更多
Lower hybrid current drive(LHCD)experiments have been done on the superconducting Tokamak HT-7 by using a new developed long pulse megawatt lower hybrid wave system.An LHCD efficiency of 0.5×10^(19)A·m^(-2)/...Lower hybrid current drive(LHCD)experiments have been done on the superconducting Tokamak HT-7 by using a new developed long pulse megawatt lower hybrid wave system.An LHCD efficiency of 0.5×10^(19)A·m^(-2)/W in a pulse length of several hundreds of milliseconds has been achieved.After boronization of the tokamak vacuum vessel,considerable improvements of plasma energy confinement and particle confinement during LHCD phase have been achieved by adjusting wave spectra.An energy transfer from the lower hybrid wave to plasma bulk electrons has been demonstrated experimentally.A computer simulation of the LHCD experiments by using a ray tracing code combined with a two dimensional Fokker-Planck code is in good accordance with experimental measurements and suggests an important role of plasma current profile.展开更多
In this paper, the composition of HT-7 LHCD system along with its protection systems is introduced. It is very important for us to run the LHCD system safely and efficiently.
In this paper, the technology of the phase adjustment of a lower hybrid wave on HT7 superconducting tokamak is described and the calculating method involved in the technology is introduced. The design method of hardw...In this paper, the technology of the phase adjustment of a lower hybrid wave on HT7 superconducting tokamak is described and the calculating method involved in the technology is introduced. The design method of hardware and software is also presented. In addition, a series of experimental results are reported.展开更多
文摘Ramp-up experiments by means of lower hybrid wave on HT-7 superconducting tokamak have been performed and analyzed. A ramp-up rate of over 300 kA/s is obtained and a conversion efficiency of over 1.0% has been achieved during the ramp-up phase. The study of the dependence of conversion efficiency on plasma density shows that the conversion efficiency is affected by the driven current, which is mainly dominated by the competition of impurity concentration with wave accessibility condition. In addition, the effect of current profile may play an important role in determining the conversion efficiency.
文摘Lower hybrid current drive experiments on the HT-7 device have been carried out by scanning the following parameters: central line averaged electron density (ne = 0.6 - 2.0 × 1019m-3) and toroidal magnetic field (Bt = 1.62 - 2.0 T). The dependence of current drive efficiency on these parameters has been studied and the experimental curves of current drive efficiency as a function of ne and Bt have also been obtained. From these experimental results, it can be seen that current drive efficiency rises with the increase of toroidal magnetic field. As plasma density increases, the current drive efficiency first increases to a certain value, then gradually decreases, that is, there exists an optimized density regime where a better drive efficiency can be obtained. The analysis shows that the current drive efficiency is mainly affected by wave accessibility and impurity concentration, and the competition of these two factors determines the current drive efficiency.
文摘Lower hybrid current drive(LHCD)experiments have been done on the superconducting Tokamak HT-7 by using a new developed long pulse megawatt lower hybrid wave system.An LHCD efficiency of 0.5×10^(19)A·m^(-2)/W in a pulse length of several hundreds of milliseconds has been achieved.After boronization of the tokamak vacuum vessel,considerable improvements of plasma energy confinement and particle confinement during LHCD phase have been achieved by adjusting wave spectra.An energy transfer from the lower hybrid wave to plasma bulk electrons has been demonstrated experimentally.A computer simulation of the LHCD experiments by using a ray tracing code combined with a two dimensional Fokker-Planck code is in good accordance with experimental measurements and suggests an important role of plasma current profile.
文摘In this paper, the composition of HT-7 LHCD system along with its protection systems is introduced. It is very important for us to run the LHCD system safely and efficiently.
基金This work is supported by the National Nature Science Foundation of China No.19975048.
文摘In this paper, the technology of the phase adjustment of a lower hybrid wave on HT7 superconducting tokamak is described and the calculating method involved in the technology is introduced. The design method of hardware and software is also presented. In addition, a series of experimental results are reported.
