Post-mortem methods cannot fulfill the requirement of monitoring the lifetime of the plasma facing components （PFC） and measuring the tritium inventory for the safety evaluation. Laserinduced breakdown spectroscopy ...Post-mortem methods cannot fulfill the requirement of monitoring the lifetime of the plasma facing components （PFC） and measuring the tritium inventory for the safety evaluation. Laserinduced breakdown spectroscopy （LIBS） is proposed as a promising method for the in situ study of fuel retention and impurity deposition in a tokamak. In this study, an in situ LIBS system was successfully established on EAST to investigate fuel retention and impurity deposition on the first wall without the need of removal tiles between plasma discharges. Spectral lines of D, H and impurities （Mo, Li, Si ） in laser-induced plasma were observed and identified within the wavelength range of 500-700 nm. Qualitative measurements such as thickness of the deposition layers, element depth profile and fuel retention on the wall are obtained by means of in situ LIBS. The results demonstrated the potential applications of LIBS for in situ characterization of fuel retention and co-deposition on the first wall of EAST.展开更多
Fully non-inductive plasma start-up was successfully achieved by using a well- controlled microwave source on the spherical tokamak, QUEST. Non-inductive plasmas were maintained for approximately 3-5 min, during which...Fully non-inductive plasma start-up was successfully achieved by using a well- controlled microwave source on the spherical tokamak, QUEST. Non-inductive plasmas were maintained for approximately 3-5 min, during which time power balance estimates could be achieved by monitoring wall and cooling-water temperatures. Approximately 70%-90% of the injected power could be accounted for by calorimetric measurements and approximately half of the injected power was found to be deposited on the vessel wall, which is slightly dependent on the magnetic configuration. The power distribution to water-cooled limiters, which are expected to be exposed to local heat loads, depends significantly on the magnetic configuration, however some of the deposited power is due to energetic electrons, which have large poloidal orbits and are likely to be deposited on the plasma facing components.展开更多
This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder （FEB-E）. The rela...This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder （FEB-E）. The relationships between the surface temperature of a liquid lithium curtain and the effective plasma charge, fuel dilution and fusion power production have been derived. Results indicate that under normal operation, the evaporation of liquid lithium does not seriously affect the effective plasma charge, but effects on fuel dilution and fusion power are more sensitive. As an example, it has investigated the relationships between the liquid lithium curtain flow velocity and the rise of surface temperature based on operation scenario II of the FEB-E design with reversed shear configuration and high power density. Results show that even if the liquid lithium curtain flow velocity is as low as 0.5 m/s, the effects of evaporation from the liquid lithium curtain on plasma are negligible. In the present design, the sputtering of liquid lithium curtain and the particle removal effects of the divertor are not yet considered in detail. Further studies are in progress, and in this work implication of lithium erosion and divertor physics on fusion reactor operation are discussed.展开更多
A new compact cascaded arc device for plasma-wall interaction study is developed at the Institute of Plasma Physics,Chinese Academy of Sciences.A magnetic field up to 0.8 T is achieved to confine plasmas in a 1.2 m lo...A new compact cascaded arc device for plasma-wall interaction study is developed at the Institute of Plasma Physics,Chinese Academy of Sciences.A magnetic field up to 0.8 T is achieved to confine plasmas in a 1.2 m long and 0.1 m diameter vacuum chamber.Gas fluid type analysis in this compact vacuum system was done under high particle flux condition.The gas pressure obtained by calculation was consistent with the measurement result.Continuous argon plasma discharge with ion flux of~0.5×10^(24)m^(-2)s^(-1)is successfully sustained for more than 1h.The effects of magnetic field configuration,gas flow rate,and discharge arc current on the ion flux to target were studied in detail.展开更多
A kinetic simulation model has been employed to study the properties of an electronegative magnetized plasma sheath assuming the cut-off distribution of electrons and negative ions.The fundamental kinetic Bohm conditi...A kinetic simulation model has been employed to study the properties of an electronegative magnetized plasma sheath assuming the cut-off distribution of electrons and negative ions.The fundamental kinetic Bohm condition for the electronegative magnetized plasma has paramount importance for the formation of a stationary plasma sheath near the material wall.The presence of an oblique magnetic field in an electronegative plasma affects the ion distribution at the plasma injection side and at the wall.The temperature profile of negative charged particles has a non-uniform distribution,which determines the energy flow towards the wall.展开更多
由于低质量数材料不可接受的高腐蚀率以及氚共沉积的问题,未来聚变堆中更希望使用全钨壁。由于钨在芯部的高辐射冷却率,芯部的钨杂质浓度需要限制在非常低的水平(约10^(-5))。中国聚变工程试验堆(China Fusion Engineering Test Reactor...由于低质量数材料不可接受的高腐蚀率以及氚共沉积的问题,未来聚变堆中更希望使用全钨壁。由于钨在芯部的高辐射冷却率,芯部的钨杂质浓度需要限制在非常低的水平(约10^(-5))。中国聚变工程试验堆(China Fusion Engineering Test Reactor,CFETR)要求其高功率稳态运行,全钨壁是优先考虑的方案。为了估计全钨壁CFETR的芯部钨杂质浓度,用边界等离子体物理模拟软件SOLPS(Scrape-off Layer Plasma Simulation)对下单零偏滤器位形不同氖气(Ne)辐射杂质注入速率下模拟得到边界等离子体背景,再利用蒙特卡罗杂质输运程序DIVIMP(DIVertor and IMPurity)对钨杂质的输运进行了模拟。当Ne注入速率较低、靶板温度仍然较高时,即使仅考虑靶板为钨材料,芯部钨杂质浓度依然过高。当外靶板峰值温度降低至约10 eV时,钨靶板对芯部钨杂质浓度的贡献降至可接受的水平;但当包含主等离子体室壁的贡献时,芯部钨杂质浓度仍然达到10^(-4)的水平。因此当Ne杂质注入速率较高时,过高的芯部钨杂质浓度主要来源于主等离子体室壁。未来的工作中需要进一步关注钨壁对芯部钨杂质浓度的影响。展开更多
The recently modified EMC3-EIRENE code package has been widely applied as an edge-plasma analysis tool and resulted in successful validation against various measured trends seen in stellarator and tokamak plasma bound...The recently modified EMC3-EIRENE code package has been widely applied as an edge-plasma analysis tool and resulted in successful validation against various measured trends seen in stellarator and tokamak plasma boundaries.It has been shown that the code package applied for Wendelstein 7-X(W7-X)discharges in the interpretive mode can assess the impact of impurity effects on the electron density,measured by a set of Langmuir probes.In particular the spatial quantification of impurities and effects from the effective charge state Zeff and effective mass meff,which are non-trivial to record by diagnostics,were examined.The results showed that earlier assumptions of the effective charge-state distribution and effective mass for reported Langmuir probe measurements must be revised.Subsequently,reprocessing these measurements with code-interpreted spatial profiles of the effective charge state and effective mass led to an overall improved physical consistency.展开更多
基金Supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2013GB105002,2015GB109001,and 2013GB109005)National Natural Science Foundation of China(Nos.11575243,11605238,11605023)+1 种基金Chinesisch-Deutsches Forschungs Project(GZ765)Korea Research Council of Fundamental Science and Technology(KRCF)under the international collaboration&research in Asian countries(PG1314)
文摘Post-mortem methods cannot fulfill the requirement of monitoring the lifetime of the plasma facing components （PFC） and measuring the tritium inventory for the safety evaluation. Laserinduced breakdown spectroscopy （LIBS） is proposed as a promising method for the in situ study of fuel retention and impurity deposition in a tokamak. In this study, an in situ LIBS system was successfully established on EAST to investigate fuel retention and impurity deposition on the first wall without the need of removal tiles between plasma discharges. Spectral lines of D, H and impurities （Mo, Li, Si ） in laser-induced plasma were observed and identified within the wavelength range of 500-700 nm. Qualitative measurements such as thickness of the deposition layers, element depth profile and fuel retention on the wall are obtained by means of in situ LIBS. The results demonstrated the potential applications of LIBS for in situ characterization of fuel retention and co-deposition on the first wall of EAST.
基金supported by Grant-in-Aid for JSPS Fellows(KAKENHI Grant Number 16H02441,24656559)performed with the support and under the auspices of the NIFS Collaboration Research Program(NIFS05KUTRO14,NIFS11KUTR061,NIFS13KUTR085,NIFS14KUTR103)+1 种基金supported in part by the Collaborative Research Program of the Research Institute for Applied Mechanics,Kyushu Universitypartly supported by the JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics(No.11261140328)
文摘Fully non-inductive plasma start-up was successfully achieved by using a well- controlled microwave source on the spherical tokamak, QUEST. Non-inductive plasmas were maintained for approximately 3-5 min, during which time power balance estimates could be achieved by monitoring wall and cooling-water temperatures. Approximately 70%-90% of the injected power could be accounted for by calorimetric measurements and approximately half of the injected power was found to be deposited on the vessel wall, which is slightly dependent on the magnetic configuration. The power distribution to water-cooled limiters, which are expected to be exposed to local heat loads, depends significantly on the magnetic configuration, however some of the deposited power is due to energetic electrons, which have large poloidal orbits and are likely to be deposited on the plasma facing components.
基金Project supported by the National Natural Science Foundation of China （Grant No 10085001）, and in part the U.S. Department of Energy （Contract No W-31-109-ENG-38）.
文摘This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder （FEB-E）. The relationships between the surface temperature of a liquid lithium curtain and the effective plasma charge, fuel dilution and fusion power production have been derived. Results indicate that under normal operation, the evaporation of liquid lithium does not seriously affect the effective plasma charge, but effects on fuel dilution and fusion power are more sensitive. As an example, it has investigated the relationships between the liquid lithium curtain flow velocity and the rise of surface temperature based on operation scenario II of the FEB-E design with reversed shear configuration and high power density. Results show that even if the liquid lithium curtain flow velocity is as low as 0.5 m/s, the effects of evaporation from the liquid lithium curtain on plasma are negligible. In the present design, the sputtering of liquid lithium curtain and the particle removal effects of the divertor are not yet considered in detail. Further studies are in progress, and in this work implication of lithium erosion and divertor physics on fusion reactor operation are discussed.
基金supported by Comprehensive Research Facility for Fusion Technology Program of China (No. 2018000052-73-01001228)the Youth Innovation Promotion Association CAS (No. 2018484)
文摘A new compact cascaded arc device for plasma-wall interaction study is developed at the Institute of Plasma Physics,Chinese Academy of Sciences.A magnetic field up to 0.8 T is achieved to confine plasmas in a 1.2 m long and 0.1 m diameter vacuum chamber.Gas fluid type analysis in this compact vacuum system was done under high particle flux condition.The gas pressure obtained by calculation was consistent with the measurement result.Continuous argon plasma discharge with ion flux of~0.5×10^(24)m^(-2)s^(-1)is successfully sustained for more than 1h.The effects of magnetic field configuration,gas flow rate,and discharge arc current on the ion flux to target were studied in detail.
基金Suresh Basnet would like to acknowledge the University Grants Commission,Nepal for the PhD fellowship.
文摘A kinetic simulation model has been employed to study the properties of an electronegative magnetized plasma sheath assuming the cut-off distribution of electrons and negative ions.The fundamental kinetic Bohm condition for the electronegative magnetized plasma has paramount importance for the formation of a stationary plasma sheath near the material wall.The presence of an oblique magnetic field in an electronegative plasma affects the ion distribution at the plasma injection side and at the wall.The temperature profile of negative charged particles has a non-uniform distribution,which determines the energy flow towards the wall.
基金This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under Grant Agreement No.633053.
文摘The recently modified EMC3-EIRENE code package has been widely applied as an edge-plasma analysis tool and resulted in successful validation against various measured trends seen in stellarator and tokamak plasma boundaries.It has been shown that the code package applied for Wendelstein 7-X(W7-X)discharges in the interpretive mode can assess the impact of impurity effects on the electron density,measured by a set of Langmuir probes.In particular the spatial quantification of impurities and effects from the effective charge state Zeff and effective mass meff,which are non-trivial to record by diagnostics,were examined.The results showed that earlier assumptions of the effective charge-state distribution and effective mass for reported Langmuir probe measurements must be revised.Subsequently,reprocessing these measurements with code-interpreted spatial profiles of the effective charge state and effective mass led to an overall improved physical consistency.
