作者机构:
[Yin, Lan; Chen, You; Huang, Qianhong; Song, Chengyi; Xia, Yanbo; Gong, Xueyu] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Yang, Cheng] Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China.;[Zheng, Pingwei] Univ South China, Sch Resource & Environm & Safety Engn, Hengyang 421001, Peoples R China.
通讯机构:
[Song, Chengyi] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.
关键词:
CFETR;ICRF;bulk ion heating
摘要:
For a fusion device, plasma pre-heating is required before the self-sustaining burning-state reactions of deuterium (D) and tritium (T) commence. Plasma heating with waves in the ion-cyclotron range of frequencies (ICRF) is effective in tokamaks. A new three-ion ICRF heating scheme for plasmas in the Chinese Fusion Engineering Test Reactor (CFETR) that require an increase in the bulk ion temperature via heating the lithium impurities in the D-T plasmas, was studied numerically. Our simulations show that the radio-frequency wave power is strongly absorbed by very few Li-7 ions with concentrations of 0.01%-0.2% in a suitable mixture of D-T plasmas, the enhanced minority ion heating is related to that the Li-7 fundamental resonance layer is very close to the two mode conversion layers. In adjusting the mixtures over a wide range of composition, an oscillatory behaviour in the Li-7 absorption efficiency arises because of interference. Moreover, from estimates of the Li-7 ion tail energy, most of the tail energy of the minority ions is found to be transferred to background ions via collisions. Compared with the routine (He-3)-D-T scheme, the ICRF power is absorbed more effectively by the Li-7 ions in the (Li-7)-D-T heating scenario, and after the Fokker-Planck equations were solved, a large fraction of bulk ion heating was evident in the (Li-7)-D-T heating scenario. The new three-ion scenario may therefore be an attractive proposition for bulk ion heating during the activated phase of the reactor.
作者机构:
[Fu Jia; Lyu Bo; Bin Bin; Li Yichao; Wan Shunkuan; Zhang Hongming; Li Yingying; Wang Fudi; He Liang] Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China.;[Wang Xunyu; Yang Jin; Cao Jinjia; Gong Xueyu; He Liang] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Yu Qingjiang; Chen Jun] Univ Sci & Technol China, Dept Engn & Appl Phys, Hefei 230026, Peoples R China.
摘要:
Spectral measurement of tungsten (W) impurity is essential to study impurity transport. Therefore, an X-ray crystal spectrometer (XCS) on EAST was used to measure the line spectra from highly ionized W ions. On EAST, both poloidal XCS and tangential XCS have been developed to measure the plasma temperature as well as the rotation velocity. Recently, He-like and H-like argon spectra have also been obtained using a two-crystal setup. W lines are identified in this study. Through a careful analysis, the W lines of 3.9336, 3.9321, and 3.664 angstrom are found to be diffracted by He-like or H-like crystals. The lines are confirmed with the NIST database. We also calculated the ion temperature with Doppler broadening of these lines. The ion temperature from the W lines is entirely consistent with that from Ar line spectra. The measurement of these W line spectra could be used to study W impurity transport in future work.
摘要:
Heating with the wave in the ion cyclotron range of frequencies (ICRF) has been used in the development of high-performance H-mode operations in EAST. A different ion cyclotron resonance heating scenario in three-ion component plasma with real experimental parameters on EAST was investigated using a numerical tool. Excellent radio frequency wave absorption was found with an extremely low He-3 concentration (0.1%-0.4%) in D-H-(He-3) plasma, by adjusting the plasma composition appropriately in our simulation. In this case, the He-3 fundamental resonance layer is located between the two ion-ion hybrid resonance-cutoff pairs in close proximity, and therefore E + of the wave was considerably enhanced near the He-3 fundamental resonance layer. The minority He-3 tail was estimated to be superenergetic (similar to 1MeV) because of the high power carried by each resonant He-3 ion. The potential of the three-ion ICRF heating means on EAST was shown, and the scenarios investigated are particularly promising for fast particle generation schemes.
作者:
Du, Dan*;Xiang, Dong;Cao, Jin Jia;Yin, Lan;Zhong, Yi Jun;...
期刊:
Journal of the Physical Society of Japan,2019年88(5) ISSN:0031-9015
通讯作者:
Du, Dan
作者机构:
[Yin, Lan; Du, Dan; Zhong, Yi Jun] Univ South China, Dept Math & Phys, Hengyang 421001, Peoples R China.;[Cao, Jin Jia; Gong, Xue Yu; Xiang, Dong] Univ South China, Dept Nucl Sci & Technol, Hengyang 421001, Peoples R China.
通讯机构:
[Du, Dan] U;Univ South China, Dept Math & Phys, Hengyang 421001, Peoples R China.
作者:
Yuan, Y.;Lu, X. Q.*;Dong, J. Q.;Gong, X. Y.;Zhang, R. B.
期刊:
PHYSICS OF PLASMAS,2018年25(1):012510 ISSN:1070-664X
通讯作者:
Lu, X. Q.
作者机构:
[Yuan, Y.; Gong, X. Y.; Lu, X. Q.] Univ South China, Sch Nucl & Technol, Hengyang 421001, Peoples R China.;[Dong, J. Q.] Southwestern Inst Phys, Chengdu 610041, Sichuan, Peoples R China.;[Zhang, R. B.] Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Anhui, Peoples R China.
通讯机构:
[Lu, X. Q.] U;Univ South China, Sch Nucl & Technol, Hengyang 421001, Peoples R China.
关键词:
plasma magnetohydrodynamics;plasma simulation;plasma transport processes;tearing instability
摘要:
The effect of helical driven current on the m = 2/n = 1 tearing mode is studied numerically in a cylindrical geometry using the method of reduced magneto-hydro-dynamic simulation. The results show that the local persistent helical current drive from the beginning time can be applied to control the tearing modes, and will cause a rebound effect called flip instability when the driven current reaches a certain value. The current intensity threshold value for the occurrence of flip instability is about 0.00087I0. The method of controlling the development of tearing mode with comparative economy is given. If the local helical driven current is discontinuous, the magnetic island can be controlled within a certain range, and then, the tearing modes stop growing; thus, the flip instability can be avoided. We also find that the flip instability will become impatient with delay injection of the driven current because the high order harmonics have been developed in the original O-point. The tearing mode instability can be controlled by using the electron cyclotron current drive to reduce the gradient of the current intensity on the rational surfaces.
摘要:
Localized current drive by electron cyclotron (EC) waves is of significant importance in the outer half region of tokamak plasmas. Using the coupled GENRAY/CQL3D suite codes, a systematic comparative study between Ohkawa current drive (OKCD) and electron cyclotron current drive (ECCD) is performed. The results show that OKCD has more advantages than ECCD for far off-axis localized current drive in tokamaks with large inverse aspect ratios, while ECCD is more efficient than OKCD in tokamaks with low inverse aspect ratios. The results of local current driving on the q = 2 rational surface show that both OKCD and ECCD are effective for control of the m = 2/n = 1 tearing mode or neoclassical tearing mode (NTM). It seems that efficient Ohkawa current can be driven in a specific far off-axis radial position as long as the local inverse aspect ratio is large enough. The effect of collisionality imposes a significant impact on OKCD and results in reduction of the net current driven by unit EC power. The dimensionless current drive efficiency of OKCD increases with increasing electron beta βe in a medium range. The results further confirm that OKCD can be a valuable alternative localized current drive method to replace ECCD in large inverse aspect ratio tokamaks or in the radial position where the local inverse aspect ratio is large enough.
作者:
Zhong, Siyao;Huang, Qianhong*;Gong, X. Y.*;Zhang, Neng;Dong, J. Q.;...
期刊:
PHYSICS OF PLASMAS,2017年24(10):102519 ISSN:1070-664X
通讯作者:
Huang, Qianhong;Gong, X. Y.
作者机构:
[Zhong, Siyao; Su, JiaHao; Huang, Qianhong; Gong, X. Y.] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Hunan, Peoples R China.;[Zhang, Neng; Dong, J. Q.] Southwestern Inst Phys, POB 432, Chengdu 610041, Sichuan, Peoples R China.;[Dong, J. Q.] Zhejiang Univ, Inst Fus Theory & Simulat, Hangzhou 310058, Zhejiang, Peoples R China.
通讯机构:
[Huang, QH; Gong, XY] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Hunan, Peoples R China.
关键词:
eigenvalues and eigenfunctions;electron traps;plasma impurities;plasma temperature;plasma toroidal confinement;plasma transport processes;Tokamak devices
摘要:
The coupling of the short wavelength ion temperature gradient mode (SWITG) and trapped electron mode (SWTEM) in the presence of impurity ions is numerically studied in tokamak plasmas. It is found that the coupling of SWITG and SWTEM modes is divided into hybrid and coexistent cases. The impurity ions always have stabilizing effects on the hybrid mode (namely, SWTE-ITG) with small ηi (ηi < 0.5), which is different from the conventional TE-ITG mode. In the lager ηi (ηi > 0.5) regime, the impurity ions with the density profiles peaked inwardly (outwardly) stabilize (destabilize) the SWTE-ITG mode. Another new finding in this paper is that the impurity ions stabilize the SWTEM mode independent of whether their density profile is peaked inwardly or outwardly. The result for the SWITG mode is similar to the SWTE-ITG mode in the lager ηi regime, except that the excitation of the SWTEM mode requires ηi higher than a certain threshold. In addition, the kθρs spectra, eigenmode structures, and the effects of different impurity ion species on the modes are discussed.