Search

Your search keyword '"Niu, Guojian"' showing total 17 results
Start Over Author "Niu, Guojian" Publication Year Range Last 50 years
17 results on '"Niu, Guojian"'

3. Experimental and modeling study of the impact of upstream D2 puff on divertor detachment and impurity control with argon seeding in EAST.

Author

He, Tao, Yang, Zhongshi, Li, Kedong, Wang, Liang, Jia, Guozhang, Liu, Xiaoju, Niu, Guojian, Lin, Xin, Nian, Feifei, Wang, Rong, Wu, Kai, Yu, Lin, Meng, Lingyi, Liang, Ruirong, Wang, Minrui, Zhang, Ling, Zhang, Tao, Mao, Songtao, Zang, Qing, and Ding, Fang

Subjects
ARGON, HEAT flux, HEATING control, DEUTERIUM, ELECTRIC fields, HEATING load
Abstract

Radiative divertor is an effective method for the divertor heat flux control, but excessive core impurity radiation can deteriorate the confinement in tokamaks. In recent EAST experiments, the compatibility of divertor detachment and impurity control with good core confinement (H98,y2 ∼1) has been achieved simultaneously by combining an upstream deuterium (D2) puff and divertor argon (Ar) seeding. Both experimental and SOLPS-ITER modeling reveal that additional D2 puff can further mitigate the target heat load and facilitate the detachment. The SOLPS-ITER results also show that the D2 puff makes a limited contribution to the Ar line radiation but a significant contribution to the neutral radiation in the SOL and divertor regions. The physical mechanism behind the effect of the D2 puff on the Ar retention is also revealed by the modeling. The increase in the Ar velocity is the major reason for the improved Ar retention in the partial detachment state. The increase in vAr is mainly caused by the strengthening of frictional drag of D+, which is because the additional D2 puff increases the pressure gradient force (FPG) and the electric field force (FE) on D+. Further analysis reveals that in the deep detachment state, some other negative effects play a dominant role in determining the Ar retention, such as the shift of the region of the Ar+ ionization source, the decrease in the strength of the Ar+ ionization source, and the net force on the Ar ions near the target. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

10. Experimental study of the influence of gas puff locations on H-mode boundary plasmas with argon seeding on EAST

Author

He, Tao, primary, Yang, Zhongshi, additional, Wang, Liang, additional, Li, Kedong, additional, Wang, Huiqian, additional, Eldon, David, additional, Hyatt, Alan, additional, Humphreys, David, additional, Meng, Lingyi, additional, Ding, Fang, additional, Wang, Yuming, additional, Duan, Yanmin, additional, Zhang, Ling, additional, Xu, Jichan, additional, Luo, Yu, additional, Ye, Dawei, additional, Chen, Xiahua, additional, Yang, Qingquan, additional, Nian, Feifei, additional, Niu, Guojian, additional, Xu, Guosheng, additional, and Luo, Guang-Nan, additional

Published
2021
Full Text
View/download PDF

11. A Molecular Dynamics Study on the Dust-Plasma/Wall Interactions in the EAST Tokamak

Author

Niu Guojian (牛国鉴), Luo Guangnan (罗广南), Hong Rongjie (洪荣杰), and Yang Zhongshi

Subjects
Tokamak, chemistry.chemical_element, Radius, Plasma, Tungsten, Edge (geometry), Condensed Matter Physics, Deuterium plasma, law.invention, Ion, Molecular dynamics, chemistry, law, Atomic physics
Abstract

The interactions between the W nano-dust and deuterium plasma at different locations of the EAST tokamak are simulated using a molecular dynamics code. It is shown that nano-dust particles, with the radius, Rd, ~5 nm, can exist for at least several nano-seconds under the interactions from the ions without being ablated in some specific places of the tokamak edge plasma, while those with Rd ≥25 nm may be ablated if the plasma temperature T~ 50 eV and density n~1019 m−3. In addition, the collisions of tungsten nano-dust grains with a tungsten wall at 100 m/s or 1000 m/s impinging speeds are simulated. It is demonstrated that the dust will stick to the wall, and the collision will not cause substantial damage to the wall, but it may be able to cause partial destruction of the dust grains themselves depending on their incident speeds.

Published
2013

Catalog

Books, media, physical & digital resources
See catalog results