SMBI (supersonic molecular beam injection), as an effective fueling method for fusion plasmas, has been widely used on the HL-2A tokamak and other fusion devices. Two different types of SMBI system are now installed...SMBI (supersonic molecular beam injection), as an effective fueling method for fusion plasmas, has been widely used on the HL-2A tokamak and other fusion devices. Two different types of SMBI system are now installed on HL-2A. One is an electromagnetic valve injector on the low field side (LFS), and the other is a pneumatic valve injector on the high field side (HFS). A new electron density record nc = 4.7× 10^19 m ^-3 which exceeds both the Oreenwald density limit and the maximum density obtained by gas puffing (GP), was obtained on HL-2A with single-null-divertor operation. The HFS injection system is still under test, however, its outstanding fueling characteristics have already been observed, e.g. it has higher fueling efficiency compared to the LFS system. This excellent feature is still preserved during the process of ECRH.展开更多
In HL-2A tokamaks, the behavior of heat flux deposited on the divertor targets has been studied during deuterium gas fuelling. The heat flux is reduced significantly after supersonic molecular beam injection (SMBI) ...In HL-2A tokamaks, the behavior of heat flux deposited on the divertor targets has been studied during deuterium gas fuelling. The heat flux is reduced significantly after supersonic molecular beam injection (SMBI) fuelling during Ohmic and electron cyclotron resonance heating (ECRH) divertor discharges. The SMBI fuelling causes an increase in the plasma density and this change results in the experienced change of the edge properties. Most of this reduction in divertor target heat flux occurs together with a high plasma radiation region located at near the X-point. The largest reduction in heat flux profiles is observed at the outboard divertor separatrix strike point, while the heat flux far from the strike point remains almost unchanged. In particular, with SMBI multi-pulses gas fuelling, a partially detached divertor regime is observed with a highly radiating region at the X-point. With the onset of the partially detached divertor regime, a sudden drop in both heat flux and power flow on the divertor target is observed. The reduction in power load on the divertor targets is roughly equal to the increase in plasma radiation loss.展开更多
Wendelstein 7-AS (W7-AS) pertains to an advanced helical stellarator. A new fuelling method, the supersonic molecular beam injection (SMBI, named Gas Jet in Germany) system was installed in W7-AS in May 2001 as a coop...Wendelstein 7-AS (W7-AS) pertains to an advanced helical stellarator. A new fuelling method, the supersonic molecular beam injection (SMBI, named Gas Jet in Germany) system was installed in W7-AS in May 2001 as a cooperation research item co-supported by the National Nature Science Foundation of China and the Max-Planck Institute of Plasma Physics, Garching, Germany. The experiments of the gas jet with hydrogen or deuterium on W7-AS were implemented. The experimental results exhibit the following features such as high fuelling efficiency, stable high-density plasmas and reduction of the recycling fluxes from the vessel wall during injection. These crucial points show that the new fuelling method can be applied to long and stable discharges.展开更多
Recently, hydrogen fueling experiments with supersonic molecular beam injection (SMBI) system have been performed in the J-TEXT tokamak. To evaluate the effects of the in- jection amount of SMBI on plasma behaviors,...Recently, hydrogen fueling experiments with supersonic molecular beam injection (SMBI) system have been performed in the J-TEXT tokamak. To evaluate the effects of the in- jection amount of SMBI on plasma behaviors, moderate and intensive SMBs have been separately injected and compared with each other in Ohmic discharges. With moderate SMBs, electron den- sity increases about twice as before, the size of magnetic island slightly decreases, and the edge toroidal rotation speed in a counter-current direction, measured by a high resolution spectrometer (Carbon V ion, 227.09 nm, r/a-= 0.7-0.8), is accelerated from 8 km/s to 12 km/s. The state of higher electron density with moderate SMBI can be maintained for a long period, which indicates that plasma confinement is improved. However, with intensive SMBs, the accompanied magne- tohydrodynamic (MHD) activities are triggered, and the electron density increases moderately. The edge toroidal velocity is decreased, in certain cases even reversed in the co-current direction. The statistical result of experimental data for moderate and intensive SMBs suggests a preferred fueling amount (less than 3.2 ~ 1019) to improve the SMBI fueling efficiency in experiments.展开更多
Density limits with different fuelling methods have been compared in HL-2A, i.e. direct gas puffing and supersonic molecular beam injection (SMBI) from outer midplane, and divertor gas fuelling. The maximum densitie...Density limits with different fuelling methods have been compared in HL-2A, i.e. direct gas puffing and supersonic molecular beam injection (SMBI) from outer midplane, and divertor gas fuelling. The maximum densities for low current discharges are 3.4×10^19 m-3, 4.3×10^19 m-3 and 4.7×10^19 m-3 for the 3 kinds of fuelling methods. The corresponding density ratios to Green- wald density limit are 0.9, 1.1, 1.2, respectively. The behavior of density limit disruption is analyzed as well.展开更多
Pneumatic and centrifugal injectors for steady-state plasma refuelling bysolid hydrogen, deuterium and tritium pellets have been designed at the PELIN Laboratory to meetrequirements of LHD, TORE SUPRA, and ITER. Prese...Pneumatic and centrifugal injectors for steady-state plasma refuelling bysolid hydrogen, deuterium and tritium pellets have been designed at the PELIN Laboratory to meetrequirements of LHD, TORE SUPRA, and ITER. Presented here is a review of these injectors' designsand results.展开更多
The pellet injection experiments for fuelling and diagnostics have been carried out on the HL-1M tokamak. The eight-pellet injector was installed on HL-1M. A reliable monitordetector and camera system was set up to ta...The pellet injection experiments for fuelling and diagnostics have been carried out on the HL-1M tokamak. The eight-pellet injector was installed on HL-1M. A reliable monitordetector and camera system was set up to take initial pellet photographs and measure the initial pellet speed and size. High fuelling efficiency of 60 % - 100 % and a density profile with a peaking factor of 1.8 - 2.0 were obtained. The maximum density close to 10^14/cm^3 in HL-1M was achieved with newly optimized combined fuelling techniques. Two typical models of pellet ablation have been utilized for simulative calculation of the ablation rates in HL-1M. In comparison with the distribution of the measured Hα emission intensity from the digital data of the CCD camera, the experimental result seems more optimistic for core fuelling than theoretical predictions by the two models. The safety factor profile q(r) has been extracted from the information provided by the CCD camera during the pellet injection. The reliability of the measured results depends mainly on the calibration of the imaging space position. Based on the calibration, the measured q-profile becomes more reasonable than those published previously for the same shot number and same photograph.展开更多
The fusion performance and particle confinement of an international thermonuclear experimental reactor(ITER)-like fusion device have been modeled by numerically solving the energy transport equation and the particle...The fusion performance and particle confinement of an international thermonuclear experimental reactor(ITER)-like fusion device have been modeled by numerically solving the energy transport equation and the particle transport equation. The effect of fuelling depth has been investigated. The plasma is primarily heated by the fusion produced alpha particles and the loss process of particles and energy in the scrape-off layer has been taken into account. To study the effect of fuelling depth on fusion performance, the ITERH-98P(y,2) scaling law has been used to evaluate the transport coefficients. It is shown that the particle confinement and fusion performance are significantly dependent on the fuelling depth. Deviation of 10% of the minor radius on fuelling depth can make the particle confinement change by ~ 61% and the fusion performance change by ~ 108%. The enhancement of fusion performance is due to the better particle confinement induced by deeper particle fuelling.展开更多
Large-scale applications of fuel-cell vehicles(FCVs)are of vital importance to reduce emissions of greenhouse gases in the transportation sector,especially in the heavy-duty and long-distance scenarios.Efficient fuell...Large-scale applications of fuel-cell vehicles(FCVs)are of vital importance to reduce emissions of greenhouse gases in the transportation sector,especially in the heavy-duty and long-distance scenarios.Efficient fuelling for the on-board gaseous hydrogen cylinders of an FCV is essential to achieve a fuelling experience that is comparable to that of traditional fossil-fuel-powered vehicles.However,the heating effect during refuelling leads to potential safety issues when the hydrogen temperature in the cylinder exceeds 85℃.Therefore,fuelling protocols are critical to ensure the efficiency and safety of the hydrogen mobility infrastructure.In this paper,the fuelling protocols for FCV vans and buses with type III cylinders were developed and the pre-cooling temperatures were optimized to minimize the energy consumption.Their performance was demonstrated with a 35-MPa hydrogen fuelling station.We found that FCV vans and buses can be safely refuelled in 3 or 5 minutes at a minimum,respectively,demonstrating a fuelling experience that is similar to that of traditional vehicles.展开更多
基金supported by National Natural Science Foundation of China (Nos.10675043, 10975049)Chinese National Fusion Project for ITER (No.2009GB104007)
文摘SMBI (supersonic molecular beam injection), as an effective fueling method for fusion plasmas, has been widely used on the HL-2A tokamak and other fusion devices. Two different types of SMBI system are now installed on HL-2A. One is an electromagnetic valve injector on the low field side (LFS), and the other is a pneumatic valve injector on the high field side (HFS). A new electron density record nc = 4.7× 10^19 m ^-3 which exceeds both the Oreenwald density limit and the maximum density obtained by gas puffing (GP), was obtained on HL-2A with single-null-divertor operation. The HFS injection system is still under test, however, its outstanding fueling characteristics have already been observed, e.g. it has higher fueling efficiency compared to the LFS system. This excellent feature is still preserved during the process of ECRH.
基金supported by National Natural Science Foundation of China(No.10805016)the National Magnetic Confinement Fusion Science Program of China(No.2009GB104008)
文摘In HL-2A tokamaks, the behavior of heat flux deposited on the divertor targets has been studied during deuterium gas fuelling. The heat flux is reduced significantly after supersonic molecular beam injection (SMBI) fuelling during Ohmic and electron cyclotron resonance heating (ECRH) divertor discharges. The SMBI fuelling causes an increase in the plasma density and this change results in the experienced change of the edge properties. Most of this reduction in divertor target heat flux occurs together with a high plasma radiation region located at near the X-point. The largest reduction in heat flux profiles is observed at the outboard divertor separatrix strike point, while the heat flux far from the strike point remains almost unchanged. In particular, with SMBI multi-pulses gas fuelling, a partially detached divertor regime is observed with a highly radiating region at the X-point. With the onset of the partially detached divertor regime, a sudden drop in both heat flux and power flow on the divertor target is observed. The reduction in power load on the divertor targets is roughly equal to the increase in plasma radiation loss.
基金The project supported by the National Nature Science Foundation of China (Nos. 19775011 and 10075016) the China Nuclear Industry Science Foundation (No. 94C03033)
文摘Wendelstein 7-AS (W7-AS) pertains to an advanced helical stellarator. A new fuelling method, the supersonic molecular beam injection (SMBI, named Gas Jet in Germany) system was installed in W7-AS in May 2001 as a cooperation research item co-supported by the National Nature Science Foundation of China and the Max-Planck Institute of Plasma Physics, Garching, Germany. The experiments of the gas jet with hydrogen or deuterium on W7-AS were implemented. The experimental results exhibit the following features such as high fuelling efficiency, stable high-density plasmas and reduction of the recycling fluxes from the vessel wall during injection. These crucial points show that the new fuelling method can be applied to long and stable discharges.
基金supported by National Natural Science Foundation of China(Nos.11005043 and 11205053)the National Magnetic Confinement Fusion Program of China(No.2013GB106001)
文摘Recently, hydrogen fueling experiments with supersonic molecular beam injection (SMBI) system have been performed in the J-TEXT tokamak. To evaluate the effects of the in- jection amount of SMBI on plasma behaviors, moderate and intensive SMBs have been separately injected and compared with each other in Ohmic discharges. With moderate SMBs, electron den- sity increases about twice as before, the size of magnetic island slightly decreases, and the edge toroidal rotation speed in a counter-current direction, measured by a high resolution spectrometer (Carbon V ion, 227.09 nm, r/a-= 0.7-0.8), is accelerated from 8 km/s to 12 km/s. The state of higher electron density with moderate SMBI can be maintained for a long period, which indicates that plasma confinement is improved. However, with intensive SMBs, the accompanied magne- tohydrodynamic (MHD) activities are triggered, and the electron density increases moderately. The edge toroidal velocity is decreased, in certain cases even reversed in the co-current direction. The statistical result of experimental data for moderate and intensive SMBs suggests a preferred fueling amount (less than 3.2 ~ 1019) to improve the SMBI fueling efficiency in experiments.
基金National Natural Science Foundation of China (Nos.10675041,10775044)the JSPS-CAS Core-University Program in the field of Plasma and Nuclear Fusion
文摘Density limits with different fuelling methods have been compared in HL-2A, i.e. direct gas puffing and supersonic molecular beam injection (SMBI) from outer midplane, and divertor gas fuelling. The maximum densities for low current discharges are 3.4×10^19 m-3, 4.3×10^19 m-3 and 4.7×10^19 m-3 for the 3 kinds of fuelling methods. The corresponding density ratios to Green- wald density limit are 0.9, 1.1, 1.2, respectively. The behavior of density limit disruption is analyzed as well.
文摘Pneumatic and centrifugal injectors for steady-state plasma refuelling bysolid hydrogen, deuterium and tritium pellets have been designed at the PELIN Laboratory to meetrequirements of LHD, TORE SUPRA, and ITER. Presented here is a review of these injectors' designsand results.
基金National Natural Science Foundation of China (No. 19889502)
文摘The pellet injection experiments for fuelling and diagnostics have been carried out on the HL-1M tokamak. The eight-pellet injector was installed on HL-1M. A reliable monitordetector and camera system was set up to take initial pellet photographs and measure the initial pellet speed and size. High fuelling efficiency of 60 % - 100 % and a density profile with a peaking factor of 1.8 - 2.0 were obtained. The maximum density close to 10^14/cm^3 in HL-1M was achieved with newly optimized combined fuelling techniques. Two typical models of pellet ablation have been utilized for simulative calculation of the ablation rates in HL-1M. In comparison with the distribution of the measured Hα emission intensity from the digital data of the CCD camera, the experimental result seems more optimistic for core fuelling than theoretical predictions by the two models. The safety factor profile q(r) has been extracted from the information provided by the CCD camera during the pellet injection. The reliability of the measured results depends mainly on the calibration of the imaging space position. Based on the calibration, the measured q-profile becomes more reasonable than those published previously for the same shot number and same photograph.
基金supported by National Natural Science Foundation of China(Nos.11175178 and 11375196)the National Magnetic Confinement Fusion Science Program of China(No.2014GB113000)
文摘The fusion performance and particle confinement of an international thermonuclear experimental reactor(ITER)-like fusion device have been modeled by numerically solving the energy transport equation and the particle transport equation. The effect of fuelling depth has been investigated. The plasma is primarily heated by the fusion produced alpha particles and the loss process of particles and energy in the scrape-off layer has been taken into account. To study the effect of fuelling depth on fusion performance, the ITERH-98P(y,2) scaling law has been used to evaluate the transport coefficients. It is shown that the particle confinement and fusion performance are significantly dependent on the fuelling depth. Deviation of 10% of the minor radius on fuelling depth can make the particle confinement change by ~ 61% and the fusion performance change by ~ 108%. The enhancement of fusion performance is due to the better particle confinement induced by deeper particle fuelling.
基金supported by the National Key R&D Program of China (no.2019YFB1505204).
文摘Large-scale applications of fuel-cell vehicles(FCVs)are of vital importance to reduce emissions of greenhouse gases in the transportation sector,especially in the heavy-duty and long-distance scenarios.Efficient fuelling for the on-board gaseous hydrogen cylinders of an FCV is essential to achieve a fuelling experience that is comparable to that of traditional fossil-fuel-powered vehicles.However,the heating effect during refuelling leads to potential safety issues when the hydrogen temperature in the cylinder exceeds 85℃.Therefore,fuelling protocols are critical to ensure the efficiency and safety of the hydrogen mobility infrastructure.In this paper,the fuelling protocols for FCV vans and buses with type III cylinders were developed and the pre-cooling temperatures were optimized to minimize the energy consumption.Their performance was demonstrated with a 35-MPa hydrogen fuelling station.We found that FCV vans and buses can be safely refuelled in 3 or 5 minutes at a minimum,respectively,demonstrating a fuelling experience that is similar to that of traditional vehicles.