The steady fusion plasma operation is constrained by tungsten(W)material sputtering issue in the EAST tokamak.In this work,the suppression of W sputtering source has been studied by advanced wall conditionings.It is a...The steady fusion plasma operation is constrained by tungsten(W)material sputtering issue in the EAST tokamak.In this work,the suppression of W sputtering source has been studied by advanced wall conditionings.It is also concluded that the W sputtering yield becomes more with increasing carbon(C)content in the main deuterium(D)plasma.In EAST,the integrated use of discharge cleanings and lithium(Li)coating has positive effects on the suppression of W sputtering source.In the plasma recovery experiments,it is suggested that the W intensity is reduced by approximately 60%with the help of~35 h Ion Cyclotron Radio Frequency Discharge Cleaning(ICRF-DC)and~40 g Li coating after vacuum failure.The first wall covered by Li film could be relieved from the bombardment of energetic particles,and the impurity in the vessel would be removed through the particle induced desorption and isotope exchange during the discharge cleanings.In general,the sputtering yield of W would decrease from the source,on the bias of the improvement of wall condition and the mitigation of plasmawall interaction process.It lays important base of the achievement of high-parameter and longpulse plasma operation in EAST.The experiences also would be constructive for us to promote the understanding of relevant physics and basis towards the ITER-like condition.展开更多
By introducing different dopants into the lattice, lanthanum sulfides with higher stability were prepared via the sulfurization of lanthanum oxides using CS2 gas at 1 000 ℃. The sulfurizing time of 8 hours was optimi...By introducing different dopants into the lattice, lanthanum sulfides with higher stability were prepared via the sulfurization of lanthanum oxides using CS2 gas at 1 000 ℃. The sulfurizing time of 8 hours was optimized for La/Ca=2 at 1 000 ℃ and its sulfurization mechanism to form CaLa2S4 was via the reaction of β-La2S3 with CaS. As the increase of the La/Ca and La/Na ratio, longer sulfurizing time was required to get cubic phase. The investigation indicates that Na＋ ions were more effective to stabilize cubic structure comparing with Ca2＋ ions.展开更多
基金supported by the National Key Research and Development Program of China(Nos.2017YFE0301100 and 2017YFA0402500)National Natural Science Foundation of China(No.11605237)the Users with Excellence Program of Hefei Science Center CAS(2020HSC-UE010)。
文摘The steady fusion plasma operation is constrained by tungsten(W)material sputtering issue in the EAST tokamak.In this work,the suppression of W sputtering source has been studied by advanced wall conditionings.It is also concluded that the W sputtering yield becomes more with increasing carbon(C)content in the main deuterium(D)plasma.In EAST,the integrated use of discharge cleanings and lithium(Li)coating has positive effects on the suppression of W sputtering source.In the plasma recovery experiments,it is suggested that the W intensity is reduced by approximately 60%with the help of~35 h Ion Cyclotron Radio Frequency Discharge Cleaning(ICRF-DC)and~40 g Li coating after vacuum failure.The first wall covered by Li film could be relieved from the bombardment of energetic particles,and the impurity in the vessel would be removed through the particle induced desorption and isotope exchange during the discharge cleanings.In general,the sputtering yield of W would decrease from the source,on the bias of the improvement of wall condition and the mitigation of plasmawall interaction process.It lays important base of the achievement of high-parameter and longpulse plasma operation in EAST.The experiences also would be constructive for us to promote the understanding of relevant physics and basis towards the ITER-like condition.
基金Funded by the National High-Tech Research and Development Program of China (863 Program) (No.2009AA03Z431)
文摘By introducing different dopants into the lattice, lanthanum sulfides with higher stability were prepared via the sulfurization of lanthanum oxides using CS2 gas at 1 000 ℃. The sulfurizing time of 8 hours was optimized for La/Ca=2 at 1 000 ℃ and its sulfurization mechanism to form CaLa2S4 was via the reaction of β-La2S3 with CaS. As the increase of the La/Ca and La/Na ratio, longer sulfurizing time was required to get cubic phase. The investigation indicates that Na＋ ions were more effective to stabilize cubic structure comparing with Ca2＋ ions.
