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Preliminary simulation results obtained with the code developed for ion Bernstein wave (IBW) heating in the HT-7 tokamak are presented. Comparison of the simulation of IBW heating and an HT-7 experiment confirms that using IBW of various frequencies can result in local or global plasma heating. The studies suggest that IBW absorption by ions near the ion cyclotron resonant layer and by electrons via electron Landau damping (ELD) around the maximum of n// offers a possible mechanism of plasma heating. 相似文献
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Ramp-up experiments by means of lower hydrid wave on HT-7 superconducting tokamak have been performed and analyzed.A ramp-up rate of over 300kA/s is obtained and a conversion efficiency of over 10% has been achieved during the ramp-up phases.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. 相似文献
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Sawtooth Activity during Lower Hybrid Current Drive Experiment in HT-7 Superconducting Tokamak 总被引:1,自引:0,他引:1
1.IntroductionSawtoothoscillationisoneofthemosttypicalmagnetohydrodynamic(MHD)phenomenaobservedintokamakplasmaunderavarietyofexperimentconditions[l],especiallyinhigh-powerauxiliaryheatingexperiment.IthasattractedmuchattentionbecauseofitsstrongimpactonplasmaconfinementandprovidesagoodexamplefOrthedemonstrationofvariousMHDtheories.Forthisreasonthestabi-lizationofsatttoothhasbecomeacriticalproblemfortokamakplasma.Lowerhybridcurrentdrivethroughitschangeofthectlrrentprofilecanradicallyaltertl1e… 相似文献
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Effective Lower Hybrid Current Driving (LHCD) and improved confinement experiments in higher plasma parameters (Ip > 200 kA, ne > 2 ×1013 cm-3, Te≥ 1 keV) have been curried out in optimized LH wave spectrum and plasma parameters in HT - 7 superconducting tokamak. The dependence of current driving efficiency on LH power spectrum, plasma density ne and toroidal magnetic field BT has been obtained under optimal conditions. A good CD efficiency was obtained at higher plasma current and higher electron density. The improvement of the energy confinement time is accompanied with the increase in line averaged electron density, and in ion and electron temperatures. The highest current driving efficiency reached ηCD = IpneR/PRF≈1.05×1019 Am-2/W. Wave-plasma coupling was sustained in a good state and the reflective coefficient was less than 5%. The experiments have also demonstrated the ability of LH wave in the start-up and ramp-up of the plasma current. The measurement of the temporal distribution of plasma 相似文献
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1 IntroductionLower hybrid current drive (LHCD) has become aneffective method to maintain plasma current in a toka-mak. Plenty of experimental results on the HT-7 toka-mak also show that LHCD is an important auxiliarymeans to achieve steady state operation of the toka-mak and to obtain plasmas with improved confine-ments [1~4]. In the experiments, lower hybrid wave(LHW) with a frequency of 2.45 GHz is launched intothe plasma by an LHW antenna. Since the power spec-trum of the launched … 相似文献
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Sawtooth control experiments were performed on HT-7 with a limiter configuration and on the Experimental Advanced Superconducting Tokamak (EAST) with a double null con-figuration. The sawtooth period can be modified by lower hybrid wave (LHW) and ion cyclotron resonance frequency (ICRF). Different sawtooth behavior was observed with the same plasma density, LHW power but different plasma currents on HT-7. There was a dwell time between LHW added and the sawtooth stabilization on HT-7 while the sawtooth stabilization immediately happened when LHW power was injected on EAST. The possible mechanism of the sawtooth control is discussed in this paper. All the experimental results have proved that power deposition of the radio frequency (RF) should be the key factor for sawtooth control. 相似文献
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Experiments on lower hybrid wave(LHW)coupling were investigated in the HT-7 tokamak.Good coupling of LHW plasma has been demonstrated at different conditions in the HT-7 tokamak.Relevant results have proved that LHW-plasma coupling is affected by the phase difference between adjacent waveguides.Furthermore,the edge density around the grill and relevant coupling can be adjusted by changing the plasma line average density or the gap value between the LH grill and the last closed flux surfaces(LCFS).It is found that the coupling of LHWs becomes poor when the edge density around the LH grill is large enough in the HT-7tokamak,and that coupling remains good with a proper edge density.With increasing LHW power,it is also found that the reflection coefficients(RCs)increase due to non-linear effects under conditions of low edge recycling,but can decrease under high edge recycling.The edge density depends mainly on the competition between the ponderomotive force(PMF)and the edge recycling intensity in the HT-7 tokamak. 相似文献
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汪平 胡广海 王亮 颜宁 仲小明 徐国盛 冯喜 叶扬 丁根凡 余林 刘阿娣 段艳敏 李二众 徐立清 刘海庆 丁锐 张斌 李妙辉 丁伯江 秦成明 张新军 王晓洁 吕波 张凌 吴茗甫 臧庆 林新 邹晓岚 宋云涛 《等离子体科学和技术》2023,(4):60-69
The blob properties in I-mode and ELM-free H-mode plasmas compared to L-mode have been investigated on the EAST tokamak, including the blob detection rate Nb,size δb,lifetime τb and radial velocity vr,b.The blob properties in L-mode and I-mode are similar, and those in ELM-free H-mode are different to them. The blob Nbis smaller while τbis larger in H-mode. The experimental blob sizeδband velocity scalings vr,b-δb show a good agre... 相似文献
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