The dominant wavelength range of edge impurity emissions moves from the visible range to the vacuum ultraviolet(VUV)range,as heating power increasing in the Experimental Advanced Superconducting Tokamak(EAST).The meas...The dominant wavelength range of edge impurity emissions moves from the visible range to the vacuum ultraviolet(VUV)range,as heating power increasing in the Experimental Advanced Superconducting Tokamak(EAST).The measurement provided by the existing visible spectroscopies in EAST is not sufficient for impurity transport studies for high-parameters plasmas.Therefore,in this study,a VUV spectroscopy is newly developed to measure edge impurity emissions in EAST.One Seya-Namioka VUV spectrometer(McPherson 234/302)is used in the system,equipped with a concave-corrected holographic grating with groove density of 600 grooves mm-1.Impurity line emissions can be observed in the wavelength range ofλ=50-700 nm,covering VUV,near ultraviolet and visible ranges.The observed vertical range is Z=-350-350 mm.The minimum sampling time can be set to 5 ms under full vertical binning(FVB)mode.VUV spectroscopy has been used to measure the edge impurity emission for the 2019 EAST experimental campaign.Impurity spectra are identified for several impurity species,i.e.,lithium(Li),carbon(C),oxygen(O),and iron(Fe).Several candidates for tungsten(W)lines are also measured but their clear identification is very difficult due to a strong overlap with Fe lines.Time evolutions of impurity carbon emissions of CⅡat 134.5 nm and CⅢat 97.7 nm are analyzed to prove the system capability of time-resolved measurement.The measurements of the VUV spectroscopy are very helpful for edge impurity transport study in the high-parameters plasma in EAST.展开更多
Transport of carbon in the edge plasma of EAST with a heating power Pin of 8 MW is studied using DIVIMP code. The background plasmas for DIVIMP are taken from the results by using B2.5-Eirene code. For different plasm...Transport of carbon in the edge plasma of EAST with a heating power Pin of 8 MW is studied using DIVIMP code. The background plasmas for DIVIMP are taken from the results by using B2.5-Eirene code. For different plasma densities at the core-SOL interface and the different divertor operational regimes, namely low recycling, high recycling and detachment, the simulated results show that the impurity density in SOL is higher for the high recycling regime than that for the low recycling regime, while impurity density in SOL is lower for the detachment regime than that for both the low and high recycling regimes.展开更多
Using the natural orbitals renormalization group（NORG）method,we investigate the screening of the local spin of an Anderson impurity interacting with the helical edge states in a quantum spin Hall insulator.It is fou...Using the natural orbitals renormalization group（NORG）method,we investigate the screening of the local spin of an Anderson impurity interacting with the helical edge states in a quantum spin Hall insulator.It is found that there is a local spin formed at the impurity site and the local spin is completel.y screened by electrons in the quantum spin Hall insulator.Meanwhile,the local spin is screened dominantly by a single active natural orbital.We then show that the Kondo screening mechanism becomes transparent and simple in the framework of the natural orbitals formalism.We project the active natural orbital respectively into real space and momentum space to characterize its structure.We conilrm the spin-momentum locking property of the edge states based on the occupancy of a Bloch state on the edge to which the impurity couples.Furthermore,we study the dynamical property of the active natural orbital represented by the local density of states,from which we observe the Kondo resonance peak.展开更多
基金the National Magnetic Confinement Fusion Science Program of China(Nos.2017YFE0301300 and 2018YFE0301100)National Natural Science Foundation of China(Nos.11805231,11705151)+4 种基金ASIPP Science and Research Grant(No.DSJJ-17-03)Key Program of Research and Development of Hefei Science Center(No.2017HSC-KPRD002)Anhui Provincial Natural Sci-ence Foundation(Nos.1808085QA14 and 1908085J01)Instrument Developing Project of the Chinese Academy of Sciences(No.YJKYYQ20180013)Collaborative Innovation Program of Hefei Science Center,CAS(No.2019HSC-CIP005).
文摘The dominant wavelength range of edge impurity emissions moves from the visible range to the vacuum ultraviolet(VUV)range,as heating power increasing in the Experimental Advanced Superconducting Tokamak(EAST).The measurement provided by the existing visible spectroscopies in EAST is not sufficient for impurity transport studies for high-parameters plasmas.Therefore,in this study,a VUV spectroscopy is newly developed to measure edge impurity emissions in EAST.One Seya-Namioka VUV spectrometer(McPherson 234/302)is used in the system,equipped with a concave-corrected holographic grating with groove density of 600 grooves mm-1.Impurity line emissions can be observed in the wavelength range ofλ=50-700 nm,covering VUV,near ultraviolet and visible ranges.The observed vertical range is Z=-350-350 mm.The minimum sampling time can be set to 5 ms under full vertical binning(FVB)mode.VUV spectroscopy has been used to measure the edge impurity emission for the 2019 EAST experimental campaign.Impurity spectra are identified for several impurity species,i.e.,lithium(Li),carbon(C),oxygen(O),and iron(Fe).Several candidates for tungsten(W)lines are also measured but their clear identification is very difficult due to a strong overlap with Fe lines.Time evolutions of impurity carbon emissions of CⅡat 134.5 nm and CⅢat 97.7 nm are analyzed to prove the system capability of time-resolved measurement.The measurements of the VUV spectroscopy are very helpful for edge impurity transport study in the high-parameters plasma in EAST.
基金supported by National Natural Science Foundation of China (No.10975158)in part by the National Magnetic Fusion Program of China (No.2009GB106001)
文摘Transport of carbon in the edge plasma of EAST with a heating power Pin of 8 MW is studied using DIVIMP code. The background plasmas for DIVIMP are taken from the results by using B2.5-Eirene code. For different plasma densities at the core-SOL interface and the different divertor operational regimes, namely low recycling, high recycling and detachment, the simulated results show that the impurity density in SOL is higher for the high recycling regime than that for the low recycling regime, while impurity density in SOL is lower for the detachment regime than that for both the low and high recycling regimes.
基金Supported by National Natural Science Foundation of China under Grant Nos 11474356 and 11774422supported by the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China
文摘Using the natural orbitals renormalization group（NORG）method,we investigate the screening of the local spin of an Anderson impurity interacting with the helical edge states in a quantum spin Hall insulator.It is found that there is a local spin formed at the impurity site and the local spin is completel.y screened by electrons in the quantum spin Hall insulator.Meanwhile,the local spin is screened dominantly by a single active natural orbital.We then show that the Kondo screening mechanism becomes transparent and simple in the framework of the natural orbitals formalism.We project the active natural orbital respectively into real space and momentum space to characterize its structure.We conilrm the spin-momentum locking property of the edge states based on the occupancy of a Bloch state on the edge to which the impurity couples.Furthermore,we study the dynamical property of the active natural orbital represented by the local density of states,from which we observe the Kondo resonance peak.
