Divertor detachment achieved by injecting impurities or increasing density is always accompanied with various local radiation phenomena in the boundary or core plasma. This paper presents the formation and evolution o...Divertor detachment achieved by injecting impurities or increasing density is always accompanied with various local radiation phenomena in the boundary or core plasma. This paper presents the formation and evolution of the high-field-side(HFS) radiation belts during the neon seeding plasma discharge in upper single null configuration with two directions of toroidal magnetic field in EAST tokamak. The neon mixed with deuterium seeding can induce the divertor detachment with strong radiation belts in the HFS scrape-off layer(SOL) region. With the increase of the radiation power, the plasma discharge will transit from H-mode to L-mode, and meanwhile the radiation belts move away from the near X-point to HFS SOL. When the radiation power is high enough, the radiation belts begin to move further to the other X-point along the HFS SOL, and even cause plasma disruption. The results indicate that the behavior of the radiation belts is related to the radiation power, plasma confinement performance and state of divertor detachment, which is useful for developing better feedback control methods to achieve high-performance radiative divertor operation mode.展开更多
A series of L-mode discharges have been conducted in the new‘corner slot’divertor on the Experimental Advanced Superconducting Tokamak(EAST)to study the divertor plasma behavior through sweeping strike point.The pla...A series of L-mode discharges have been conducted in the new‘corner slot’divertor on the Experimental Advanced Superconducting Tokamak(EAST)to study the divertor plasma behavior through sweeping strike point.The plasma control system controls the strike point sweeping from the horizontal target to the vertical target through poloidal field coils,with keeping the main plasma stability.The surface temperature of the divertor target cools down as the strike point moves away,indicating that sweeping strike point mitigates the heat load.To avoid the negative effect of probe tip damage,a method based on sweeping strike point is used to get the normalized profile and study the decay length of particle and heat flux on the divertor target λ_(js),_λ(q).In the discharges with high radio-frequency(RF)heating power,electron temperature T_(e) is lower and λ_(js)is larger when the strike point locates on the horizontal target compared to the vertical target,probably due to the corner effect.In the Ohmic discharges,λ_(js),λ_(q) are much larger compared to the discharges with high RF heating power,which may be attributed to lower edge T_(e).展开更多
基金Project supported by the National Magnetic Confinement Fusion Energy Research and Development Program of China (Grant Nos. 2017YFE0301300 and 2019YFE03030000)the National Natural Science Foundation of China (Grant Nos. 12005004, 11922513, and U19A20113)Anhui Provincial Natural Science Foundation (Grant No. 2008085QA38)。
文摘Divertor detachment achieved by injecting impurities or increasing density is always accompanied with various local radiation phenomena in the boundary or core plasma. This paper presents the formation and evolution of the high-field-side(HFS) radiation belts during the neon seeding plasma discharge in upper single null configuration with two directions of toroidal magnetic field in EAST tokamak. The neon mixed with deuterium seeding can induce the divertor detachment with strong radiation belts in the HFS scrape-off layer(SOL) region. With the increase of the radiation power, the plasma discharge will transit from H-mode to L-mode, and meanwhile the radiation belts move away from the near X-point to HFS SOL. When the radiation power is high enough, the radiation belts begin to move further to the other X-point along the HFS SOL, and even cause plasma disruption. The results indicate that the behavior of the radiation belts is related to the radiation power, plasma confinement performance and state of divertor detachment, which is useful for developing better feedback control methods to achieve high-performance radiative divertor operation mode.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFE0301300)the National Natural Science Foundation of China(Grant Nos.12005257,12005004,11905143,and 11922513)+3 种基金the Fund from the Institute of Energy,Hefei Comprehensive National Science Center(Grant No.GXXT-2020-004)the CASHIPS Director’s Fund(Grant Nos.BJPY2019A01 and YZJJ2020QN13)the Special Research Assistant Funding of CAS and China Postdoctoral Science Foundation(Grant No.2020M671913)Anhui Provincial Natural Science Foundation(Grant No.2008085QA38)。
文摘A series of L-mode discharges have been conducted in the new‘corner slot’divertor on the Experimental Advanced Superconducting Tokamak(EAST)to study the divertor plasma behavior through sweeping strike point.The plasma control system controls the strike point sweeping from the horizontal target to the vertical target through poloidal field coils,with keeping the main plasma stability.The surface temperature of the divertor target cools down as the strike point moves away,indicating that sweeping strike point mitigates the heat load.To avoid the negative effect of probe tip damage,a method based on sweeping strike point is used to get the normalized profile and study the decay length of particle and heat flux on the divertor target λ_(js),_λ(q).In the discharges with high radio-frequency(RF)heating power,electron temperature T_(e) is lower and λ_(js)is larger when the strike point locates on the horizontal target compared to the vertical target,probably due to the corner effect.In the Ohmic discharges,λ_(js),λ_(q) are much larger compared to the discharges with high RF heating power,which may be attributed to lower edge T_(e).
