As one of the most effective methods for plasma heating,a neutral beam injector（NBI） achieved plasma heating and current driving for the first time in EAST 2014 experimental campaign.According to the research plan o...As one of the most effective methods for plasma heating,a neutral beam injector（NBI） achieved plasma heating and current driving for the first time in EAST 2014 experimental campaign.According to the research plan of the EAST physics experiment,the first NBI（EASTNBI-1） has been built and become operational in 2014.In this article,the latest experiment results of EAST-NBI-1 are reported as follows：（1） EAST achieves H-mode plasma in the case of NBI heating alone,（2） EAST achieves 22 s long pulse stable H-mode plasma in the case of sinndtaneous NBI and lower hybrid wave（LHW） heating.The measurement data show that the loop voltage decreased and the plasma stored energy increased obviously.The results indicate that EAST-NBI-1 has achieved plasma heating and current driving,and thus lays a foundation for the construction of EAST-NBI-2,which will be built in a few months this year.展开更多
In order to synchronize the elements of the EAST Neutral Beam Injector （NBI） spatially located in several places, a distributed Timing System （TS） is developed in this paper. The timing system provides a clock ref...In order to synchronize the elements of the EAST Neutral Beam Injector （NBI） spatially located in several places, a distributed Timing System （TS） is developed in this paper. The timing system provides a clock reference for synchronization and an interlock protection of the EAST NBI system. It sends timing signals to field devices, controls the pulse widths of the timing sequences, and provides a sampling clock for the Data Acquisition System （DAS）. The timing system also generates analog waveforms to control power supplies and gas supplies according to the operator＇s configuration. The timing system is developed on a PXI （PCI eXtensions for Instrumentation） platform consisting of a LabVIEW workstation and a timing control terminal. The timing control terminal consists of a timing node and several control interface crates. Two timing nodes are configured in one beam line. Each node is responsible for the timing sequence, analog generation and feedback control for one ion source. The architecture and implementation of the timing system are presented in this paper.展开更多
Neutral beam infection has been recognized as one of the most effective means for plasma heating. According to the research plan of the EAST physics experiment, two sets of neutral beam injectors （4-8 MW, 10-100s） w...Neutral beam infection has been recognized as one of the most effective means for plasma heating. According to the research plan of the EAST physics experiment, two sets of neutral beam injectors （4-8 MW, 10-100s） were built and operated in 2014. We present the development of the EAST neutral beam injector （NBI） and the latest experiment results obtained on the test-stand about operation of ion source, beam extraction, and measurement of key parameters. Those results show that all targets reach or almost reach the design targets. All these lay a solid foundation for the achievement of plasma heating and current drive for EAST in 2014.展开更多
Abstract Vacuum insulation of -1 MV is a common issue for the HV bushing and the accel- erator for the ITER neutral beam injector （NBI）. The HV bushing as an insulating feedthrough has a five-stage structure and eac...Abstract Vacuum insulation of -1 MV is a common issue for the HV bushing and the accel- erator for the ITER neutral beam injector （NBI）. The HV bushing as an insulating feedthrough has a five-stage structure and each stage consists of double-layered insulators. To sustain -1 MV in vacuum, reduction of electric field at several triple points existing around the double-layered insulators is a critical issue. To reduce electric field simultaneously at these points, three types of stress ring have been developed. In a voltage holding test of a full-scale mockup equipped with these stress rings, 120% of rated voltage was sustained and the voltage holding capability required in ITER was verified. In the MeV accelerator, whose target is the acceleration of a H- ion beam of 1 MeV, 200 A/mS, the gap between the grid support was extended to suppress breakdowns triggered by electric field concentration at the edge and corner of the grid support. This modi- fication improved the voltage holding capability in vacuum, and the MeV accelerator succeeded in sustaining -1 MV stably, b-~rthermore, it appeared that the H- ions beam was deflected and a part of the beam was intercepted at the acceleration grid, This causes high heat load on the grids and breakdowns during beam acceleration. To suppress the direct interception, a new grid was designed with proper aperture displacement based on a three dimensional beam trajectory analysis, As a result, 980 keV, 185 A/ms H- ion beam acceleration has been demonstrated, which is close to the ITER requirement.展开更多
A radio frequency(RF) ion source was developed for neutral beam injector in Institute of Plasma Physics, Chinese Academy of Sciences(ASIPP). A cylindrical driver based RF plasma source was tested and optimized for lon...A radio frequency(RF) ion source was developed for neutral beam injector in Institute of Plasma Physics, Chinese Academy of Sciences(ASIPP). A cylindrical driver based RF plasma source was tested and optimized for long pulse operation. Recently, the plasma source achieved 1000 s stable plasma discharge with RF power of 35 k W and source pressure of 0.7 Pa for the first time.The heat loading on each of driver components such as the Faraday shield(FS), RF coil and expansion chamber was measured by the water flow calorimeter system. The experiment results showed that FS is the component with highest heat loading and the heat loading on FS was about 65.8% of total heat loading on source. The details of the long pulse operation of RF plasma source are presented in this paper.展开更多
Two sets of neutral beam injectors(NBI-1 and NBI-2) have been mounted on the EAST tokamak since 2014. NBI-1 and NBI-2 are co-direction and counter-direction, respectively. As with indepth physics and engineering study...Two sets of neutral beam injectors(NBI-1 and NBI-2) have been mounted on the EAST tokamak since 2014. NBI-1 and NBI-2 are co-direction and counter-direction, respectively. As with indepth physics and engineering study of EAST, the ability of long pulse beam injection should be required in the NBI system. For NBIs, the most important and difficult thing that should be overcome is heat removal capacity of heat loaded components for long-pulse beam extraction. In this article, the thermal state of the components of EAST NBI is investigated using water flow calorimetry and thermocouple temperatures. Results show that(1) operation parameters have an obvious influence on the heat deposited on the inner components of the beamline,(2) a suitable operation parameter can decrease the heat loading effectively and obtain longer beam pulse length, and(3) under the cooling water pressure of 0.25 MPa, the predicted maximum beam pulse length will be up to 260 s with 50 keV beam energy by a duty factor of 0.5. The results present that, in this regard, the EAST NBI-1 system has the ability of long-pulse beam injection.展开更多
A large-area high-power radio-frequency（RF） driven ion source was developed for positive and negative neutral beam injectors at the Korea Atomic Energy Research Institute（KAERI）. The RF ion source consists of a dr...A large-area high-power radio-frequency（RF） driven ion source was developed for positive and negative neutral beam injectors at the Korea Atomic Energy Research Institute（KAERI）. The RF ion source consists of a driver region, including a helical antenna and a discharge chamber, and an expansion region. RF power can be transferred at up to 10 kW with a fixed frequency of 2 MHz through an optimized RF matching system. An actively water-cooled Faraday shield is located inside the driver region of the ion source for the stable and steady-state operations of high-power RF discharge. Plasma ignition of the ion source is initiated by the injection of argongas without a starter-filament heating, and the argon-gas is then slowly exchanged by the injection of hydrogen-gas to produce pure hydrogen plasmas. The uniformities of the plasma parameter,such as a plasma density and an electron temperature, are measured at the lowest area of the driver region using two RF-compensated electrostatic probes along the direction of the shortand long-dimensions of the driver region. The plasma parameters will be compared with those obtained at the lowest area of the expansion bucket to analyze the plasma expansion properties from the driver region to the expansion region.展开更多
The long-pulse power-supply system equipped for the 4 MW beam-power ion source is comprised of three units at ASIPP（Institute of Plasma Physics, Chinese Academy of Sciences）： one for the neutralbeam test stand and ...The long-pulse power-supply system equipped for the 4 MW beam-power ion source is comprised of three units at ASIPP（Institute of Plasma Physics, Chinese Academy of Sciences）： one for the neutralbeam test stand and two for the EAST neutral-beam injectors（NBI-1 and NBI-2, respectively）. Each power supply system consists of two low voltage and high current DC power supplies for plasma generation of the ion source, and two high voltage and high current DC power supplies for the accelerator grid system. The operation range of the NB power supply is about 80 percent of the design value, which is the safe and stable operation range. At the neutral-beam test stand, a hydrogen ion beam with a beam pulse of 150 s, beam power of 1.5 MW and beam energy of 50 ke V was achieved during the long-pulse testing experiments. The result shows that the power-supply system meets the requirements of the EAST-NBIs fully and lays a basis for achieving plasma heating.展开更多
EAST NBI束线综合测试台已研制完成并具备一台兆瓦级离子源测试运行的全套电源设备,包括离子源灯丝电源、弧电源、加速器电源、抑制极电源、偏转磁体电源及缓冲器电源等。介绍了EAST兆瓦级离子源进行起弧放电调试运行的方式,叙述了各套...EAST NBI束线综合测试台已研制完成并具备一台兆瓦级离子源测试运行的全套电源设备,包括离子源灯丝电源、弧电源、加速器电源、抑制极电源、偏转磁体电源及缓冲器电源等。介绍了EAST兆瓦级离子源进行起弧放电调试运行的方式,叙述了各套离子源电源系统的设计结构、技术特点及运行控制方式,分析了离子源电源系统稳定可靠运行需要解决的各个难点,给出了EAST束线样机进行高功率及长脉冲束引出测试运行的实验结果。展开更多
The power supply system of ion source for the Neutral Beam Injector (NBI) in the HT-7 superconducting tokamak is based on a single injector with one ion source that can deliver 700 kW of neutral beam power. Experiment...The power supply system of ion source for the Neutral Beam Injector (NBI) in the HT-7 superconducting tokamak is based on a single injector with one ion source that can deliver 700 kW of neutral beam power. Experiments and a discharges test on the ion source were successfully performed. In this paper, the circuit structures and features of every power supply are described and the results of the discharges test are presented.展开更多
Neutral beam injection （NBI） is one of the most effective ways to heat and drive plasma in a tokamak. The mega watt level neutral beam injector on the HL-2A tokamak consists of four high-power ion sources. Each sour...Neutral beam injection （NBI） is one of the most effective ways to heat and drive plasma in a tokamak. The mega watt level neutral beam injector on the HL-2A tokamak consists of four high-power ion sources. Each source is supplied by discharge, beam extraction and auxiliary power supplies. Some circuit topologies and control sequences designed for the system are presented in this paper. Some important technologies such as the notching circuit, insulated gate bipolar transistor （IGBT） series-connected switch, high-frequency switching power supply and control system based on a digital signal processor （DSP） have been used. The system can be effectively used for high current ion beam extraction, protection, ion optics and so on. The power system has been safely used in HL-2A high-parameter NBI experiments for three years. The power of NBI can be kept at higher than 0.75 MW for 1 second and the ion beam power extracted from the ion source is higher than 2 MW. The ion temperature of the plasma center is close to 2.0 keV. These results show that the design of this power system is reasonable and reliable, and it can fully meet the system requirements for NBI of the HL-2A tokamak.展开更多
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2013GB101000)
文摘As one of the most effective methods for plasma heating,a neutral beam injector（NBI） achieved plasma heating and current driving for the first time in EAST 2014 experimental campaign.According to the research plan of the EAST physics experiment,the first NBI（EASTNBI-1） has been built and become operational in 2014.In this article,the latest experiment results of EAST-NBI-1 are reported as follows：（1） EAST achieves H-mode plasma in the case of NBI heating alone,（2） EAST achieves 22 s long pulse stable H-mode plasma in the case of sinndtaneous NBI and lower hybrid wave（LHW） heating.The measurement data show that the loop voltage decreased and the plasma stored energy increased obviously.The results indicate that EAST-NBI-1 has achieved plasma heating and current driving,and thus lays a foundation for the construction of EAST-NBI-2,which will be built in a few months this year.
文摘In order to synchronize the elements of the EAST Neutral Beam Injector （NBI） spatially located in several places, a distributed Timing System （TS） is developed in this paper. The timing system provides a clock reference for synchronization and an interlock protection of the EAST NBI system. It sends timing signals to field devices, controls the pulse widths of the timing sequences, and provides a sampling clock for the Data Acquisition System （DAS）. The timing system also generates analog waveforms to control power supplies and gas supplies according to the operator＇s configuration. The timing system is developed on a PXI （PCI eXtensions for Instrumentation） platform consisting of a LabVIEW workstation and a timing control terminal. The timing control terminal consists of a timing node and several control interface crates. Two timing nodes are configured in one beam line. Each node is responsible for the timing sequence, analog generation and feedback control for one ion source. The architecture and implementation of the timing system are presented in this paper.
基金Supported by the National Magnetic Confinement Fusion Science Program of China under Grant No 2013GB101001
文摘Neutral beam infection has been recognized as one of the most effective means for plasma heating. According to the research plan of the EAST physics experiment, two sets of neutral beam injectors （4-8 MW, 10-100s） were built and operated in 2014. We present the development of the EAST neutral beam injector （NBI） and the latest experiment results obtained on the test-stand about operation of ion source, beam extraction, and measurement of key parameters. Those results show that all targets reach or almost reach the design targets. All these lay a solid foundation for the achievement of plasma heating and current drive for EAST in 2014.
文摘Abstract Vacuum insulation of -1 MV is a common issue for the HV bushing and the accel- erator for the ITER neutral beam injector （NBI）. The HV bushing as an insulating feedthrough has a five-stage structure and each stage consists of double-layered insulators. To sustain -1 MV in vacuum, reduction of electric field at several triple points existing around the double-layered insulators is a critical issue. To reduce electric field simultaneously at these points, three types of stress ring have been developed. In a voltage holding test of a full-scale mockup equipped with these stress rings, 120% of rated voltage was sustained and the voltage holding capability required in ITER was verified. In the MeV accelerator, whose target is the acceleration of a H- ion beam of 1 MeV, 200 A/mS, the gap between the grid support was extended to suppress breakdowns triggered by electric field concentration at the edge and corner of the grid support. This modi- fication improved the voltage holding capability in vacuum, and the MeV accelerator succeeded in sustaining -1 MV stably, b-~rthermore, it appeared that the H- ions beam was deflected and a part of the beam was intercepted at the acceleration grid, This causes high heat load on the grids and breakdowns during beam acceleration. To suppress the direct interception, a new grid was designed with proper aperture displacement based on a three dimensional beam trajectory analysis, As a result, 980 keV, 185 A/ms H- ion beam acceleration has been demonstrated, which is close to the ITER requirement.
基金supported by Key Program of Research and Development of Hefei Science Center,CAS (Grant No. 2016HSC-KPRD002)National Key R&D Program of China (Grant No. 2017YFE300101)National Natural Science Foundation of China (Grant Nos. 11505224,11505225,11505226,11675215)
文摘A radio frequency(RF) ion source was developed for neutral beam injector in Institute of Plasma Physics, Chinese Academy of Sciences(ASIPP). A cylindrical driver based RF plasma source was tested and optimized for long pulse operation. Recently, the plasma source achieved 1000 s stable plasma discharge with RF power of 35 k W and source pressure of 0.7 Pa for the first time.The heat loading on each of driver components such as the Faraday shield(FS), RF coil and expansion chamber was measured by the water flow calorimeter system. The experiment results showed that FS is the component with highest heat loading and the heat loading on FS was about 65.8% of total heat loading on source. The details of the long pulse operation of RF plasma source are presented in this paper.
文摘Two sets of neutral beam injectors(NBI-1 and NBI-2) have been mounted on the EAST tokamak since 2014. NBI-1 and NBI-2 are co-direction and counter-direction, respectively. As with indepth physics and engineering study of EAST, the ability of long pulse beam injection should be required in the NBI system. For NBIs, the most important and difficult thing that should be overcome is heat removal capacity of heat loaded components for long-pulse beam extraction. In this article, the thermal state of the components of EAST NBI is investigated using water flow calorimetry and thermocouple temperatures. Results show that(1) operation parameters have an obvious influence on the heat deposited on the inner components of the beamline,(2) a suitable operation parameter can decrease the heat loading effectively and obtain longer beam pulse length, and(3) under the cooling water pressure of 0.25 MPa, the predicted maximum beam pulse length will be up to 260 s with 50 keV beam energy by a duty factor of 0.5. The results present that, in this regard, the EAST NBI-1 system has the ability of long-pulse beam injection.
基金supported by the Ministry of Science,ICT and Future Planning of the Republic of Korea under the ITER Technology R&D ProgramNational R&D Program Through the National Research Foundation of Korea(NRF)Funded by the Ministry of Science,ICT&Future Planning(NRF-2014M1A7A1A03045372)
文摘A large-area high-power radio-frequency（RF） driven ion source was developed for positive and negative neutral beam injectors at the Korea Atomic Energy Research Institute（KAERI）. The RF ion source consists of a driver region, including a helical antenna and a discharge chamber, and an expansion region. RF power can be transferred at up to 10 kW with a fixed frequency of 2 MHz through an optimized RF matching system. An actively water-cooled Faraday shield is located inside the driver region of the ion source for the stable and steady-state operations of high-power RF discharge. Plasma ignition of the ion source is initiated by the injection of argongas without a starter-filament heating, and the argon-gas is then slowly exchanged by the injection of hydrogen-gas to produce pure hydrogen plasmas. The uniformities of the plasma parameter,such as a plasma density and an electron temperature, are measured at the lowest area of the driver region using two RF-compensated electrostatic probes along the direction of the shortand long-dimensions of the driver region. The plasma parameters will be compared with those obtained at the lowest area of the expansion bucket to analyze the plasma expansion properties from the driver region to the expansion region.
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2013GB101003)National Natural Science Foundation of China(No.11505225)Foundation of ASIPP(No.DSJJ-15-GC03)
文摘The long-pulse power-supply system equipped for the 4 MW beam-power ion source is comprised of three units at ASIPP（Institute of Plasma Physics, Chinese Academy of Sciences）： one for the neutralbeam test stand and two for the EAST neutral-beam injectors（NBI-1 and NBI-2, respectively）. Each power supply system consists of two low voltage and high current DC power supplies for plasma generation of the ion source, and two high voltage and high current DC power supplies for the accelerator grid system. The operation range of the NB power supply is about 80 percent of the design value, which is the safe and stable operation range. At the neutral-beam test stand, a hydrogen ion beam with a beam pulse of 150 s, beam power of 1.5 MW and beam energy of 50 ke V was achieved during the long-pulse testing experiments. The result shows that the power-supply system meets the requirements of the EAST-NBIs fully and lays a basis for achieving plasma heating.
基金The project supported by the Chinese Academy of Sciences (No. SYKXD04)
文摘The power supply system of ion source for the Neutral Beam Injector (NBI) in the HT-7 superconducting tokamak is based on a single injector with one ion source that can deliver 700 kW of neutral beam power. Experiments and a discharges test on the ion source were successfully performed. In this paper, the circuit structures and features of every power supply are described and the results of the discharges test are presented.
基金supported partly by the Fund of Science and Technology Department of Hunan Province of China(2010FJ3170)
文摘Neutral beam injection （NBI） is one of the most effective ways to heat and drive plasma in a tokamak. The mega watt level neutral beam injector on the HL-2A tokamak consists of four high-power ion sources. Each source is supplied by discharge, beam extraction and auxiliary power supplies. Some circuit topologies and control sequences designed for the system are presented in this paper. Some important technologies such as the notching circuit, insulated gate bipolar transistor （IGBT） series-connected switch, high-frequency switching power supply and control system based on a digital signal processor （DSP） have been used. The system can be effectively used for high current ion beam extraction, protection, ion optics and so on. The power system has been safely used in HL-2A high-parameter NBI experiments for three years. The power of NBI can be kept at higher than 0.75 MW for 1 second and the ion beam power extracted from the ion source is higher than 2 MW. The ion temperature of the plasma center is close to 2.0 keV. These results show that the design of this power system is reasonable and reliable, and it can fully meet the system requirements for NBI of the HL-2A tokamak.
