A toroidal soft x-ray imaging(T-SXRI)system has been developed to investigate threedimensional(3D)plasma physics on J-TEXT.This T-SXRI system consists of three sets of SXR arrays.Two sets are newly developed and locat...A toroidal soft x-ray imaging(T-SXRI)system has been developed to investigate threedimensional(3D)plasma physics on J-TEXT.This T-SXRI system consists of three sets of SXR arrays.Two sets are newly developed and located on the vacuum chamber wall at toroidal positionsφof 126.4°and 272.6°,respectively,while one set was established previously atφ=65.50.Each set of SXR arrays consists of three arrays viewing the plasma poloidally,and hence can be used separately to obtain SXR images via the tomographic method.The sawtooth precursor oscillations are measured by T-SXRI,and the corresponding images of perturbative SXR signals are successfully reconstructed at these three toroidal positions,hence providing measurement of the 3D structure of precursor oscillations.The observed 3D structure is consistent with the helical structure of the m/n=1/1 mode.The experimental observation confirms that the T-SXRI system is able to observe 3D structures in the J-TEXT plasma.展开更多
J-TEXT托卡马克是用来研究热核聚变的实验装置。数据系统是其重要组成部分,由数据采集和数据服务组成。数据采集部分选用PCI总线采集卡,采集程序用LabVIEW编写,运行在Windows操作系统之下。数据服务采用MDSplus软件包,选用Redhat Linux ...J-TEXT托卡马克是用来研究热核聚变的实验装置。数据系统是其重要组成部分,由数据采集和数据服务组成。数据采集部分选用PCI总线采集卡,采集程序用LabVIEW编写,运行在Windows操作系统之下。数据服务采用MDSplus软件包,选用Redhat Linux Enterprise为操作系统。本文阐述了该系统的数据流程与实现过程。展开更多
The J-TEXT tokamak has been operated for ten years since its first plasma obtained at the end of 2007. The diagnostics development and main modulation systems, i.e. resonant magnetic perturbation （RMP） systems and m...The J-TEXT tokamak has been operated for ten years since its first plasma obtained at the end of 2007. The diagnostics development and main modulation systems, i.e. resonant magnetic perturbation （RMP） systems and massive gas injection （MGI） systems, will be introduced in this paper. Supported by these efforts, J-TEXT has contributed to research on several topics, especially on RMP physics and disruption mitigation. Both experimental and theoretical research show that RMP could lock, suppress or excite the tearing modes, depending on the RMP amplitude, frequency difference between RMP and rational surface rotation, and initial stabilities. The plasma rotation, particle transport and operation region are influenced by the RMP. Utilizing the MGI valves, disruptions have been mitigated with pure He, pure Ne, and a mixture of He and Ar （9：1）. A significant runaway current plateau could be generated with moderate amounts of Ar injection. The RMP has been shown to suppress the generation of runaway current during disruptions.展开更多
As the basic of a deeper investigation on the turbulent transport, the fluctuation property in the boundary of the newly-reconstructed Joint Texas Experimental Tokamak （J- TEXT） is studied experimentally using the r...As the basic of a deeper investigation on the turbulent transport, the fluctuation property in the boundary of the newly-reconstructed Joint Texas Experimental Tokamak （J- TEXT） is studied experimentally using the reciprocating Langmuir four-tip probe, which has been built and operated as the primary diagnostic tool in the boundary of J-TEXT tokamak. In this paper, spatial profiles of the plasma-edge parameters are obtained, such as electron temperature, plasma density, plasma potential, poloidal electric field and their fluctuations. The results indicate the existence of a Er ×BT shear layer at the vicinity of last closed flux surface （LCFS）, with the fluctuations suppressed in varying degrees. The turbulence-induced particle and energy fluxes can be calculated by the local plasma parameters above. Convection dominates the cross-field turbulent transport in boundary plasma. Electrostatic fluctuations properties are also studied in detail with the help of numerical analysis. Statistical analysis on density fluctuation shows that, the intermittency can affect the turbulence in the scrape-off layer （SOL）.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
In order to broaden the range of the plasma parameters and provide experimental conditions for physical research into high-performance plasma,the development of the electron cyclotron resonance heating(ECRH) system fo...In order to broaden the range of the plasma parameters and provide experimental conditions for physical research into high-performance plasma,the development of the electron cyclotron resonance heating(ECRH) system for the J-TEXT tokamak was initiated in 2017.For the first stage,the ECRH system operated successfully with one 105 GHz/500 kW/1 s gyrotron in 2019.More than 400 kW electron cyclotron(EC) wave power has been injected into the plasma successfully,raising the core electron temperature to 1.5 keV.In 2022,another 105 GHz/500 kW/1 s gyrotron completed commissioning tests which signifies that the ECRH system could generate an EC wave power of 1 MW in total.Under the support of the ECRH system,various physical experiments have been carried out on J-TEXT.The electron thermal transport in ECRH plasmas has been investigated.When ECRH is turned on,the electron thermal diffusivity significantly increases.The runaway current is elevated when a disruption occurs during ECRH heating.When the injected EC wave power is 400 kW,the conversion efficiency of runaway current increases from 35% to 75%.Fast electron behavior is observed in electron cyclotron current drive(ECCD) plasma by the fast electron bremsstrahlung diagnostic(FEB).The increase in the FEB intensity implies that ECCD could generate fast electrons.A successful startup with a 200 kW ECW is achieved.With the upgrade of the ECRH system,the J-TEXT operational range could be expanded and further relevant research could be conducted.展开更多
The width of a magnetic island is an important parameter for the quantitative analysis of magnetohydrodynamic-related physics. An electron cyclotron emission radiometer(ECE) is a powerful tool that can be used to obta...The width of a magnetic island is an important parameter for the quantitative analysis of magnetohydrodynamic-related physics. An electron cyclotron emission radiometer(ECE) is a powerful tool that can be used to obtain this width, which can usually be determined from the flat temperature distribution at the O-point phase or the maxima temperature perturbation. An improved method to estimate the width of a magnetic island is proposed in this paper, and it is independent of calibration. With this method and the existing 24-channel ECE system, the width of a rotation magnetic island can be estimated. Additionally, by filtering the fluctuation ECE signal, the evolution of the magnetic island can be obtained. The results of this method are consistent with those of the integrated magnetic probe signals, which represent the relative change of the magnetic island.展开更多
The limiter target electrostatic measurement system including limiter grounding current sensors and Langmuir probes have been newly developed for the measurement of the limiter target area on the Joint-Texas Experimen...The limiter target electrostatic measurement system including limiter grounding current sensors and Langmuir probes have been newly developed for the measurement of the limiter target area on the Joint-Texas Experimental tokamak (J-TEXT). Current sensors fixed between graphite limiters and the vacuum vessel walls are used to measure the currents between limiters and vessel wall. Simultaneously, a rectangular poloidal array containing 54 Langmuir probes is embedded in the graphite tiles of limiters for a more localized measurement. Based on this system, the effect of both the plasma’s inherent behavior, including plasma motion and the 2/1 tearing mode, and the electrode biasing on probe and sensor signals have been observed and analyzed in the experiments.展开更多
Joint-TEXT （J-TEXT） is a medium-sized tokamak constructed at Huazhong University of Science and Technology. At present, the poloidal field power supply consists of three subsystem sets, namely Ohmic heating field po...Joint-TEXT （J-TEXT） is a medium-sized tokamak constructed at Huazhong University of Science and Technology. At present, the poloidal field power supply consists of three subsystem sets, namely Ohmic heating field power supply, vertical field power supply, and horizontal field power supply. The structure and function of the poloidal field （PF） power supply as well as the updated control system of the power supply is described. The new scheme uses the realtime feedback control method for the poloidal field power supply. The experimental results show that the poloidal field energized by poloidal field power supply meets the J-TEXT operational requirement perfectly.展开更多
J-TEXT, formerly TEXT-U at the University of Texas at Austin in USA, is a medium-sized tokamak at the Huazhong University of Science and Technology. The toroidal field （TF） power supply of this tokamak should provid...J-TEXT, formerly TEXT-U at the University of Texas at Austin in USA, is a medium-sized tokamak at the Huazhong University of Science and Technology. The toroidal field （TF） power supply of this tokamak should provide a current of 160 kA and a flat duration of 500 ms for the toroidal field coils to generate a maximum toroidal field of 3 T at the geometric center of the vaccum vessel. This paper presents a design of a new control system which takes the real-time feedback control option for the TF power supply operation. The system was tested successfully during the commissioning. In the first experimental campaign of J-TEXT, the system effectively controlled the power supply to provide a fiat current up to 92.5 kA and therein the TF produced reached 1.74 T, which enabled the machine to generate the first plasma successfully.展开更多
基金supported by the National Magnetic Confinement Fusion Energy R&D Program of China(Nos.2018YFE0309100 and 2019YFE03010004)National Natural Science Foundation of China(No.51821005)。
文摘A toroidal soft x-ray imaging(T-SXRI)system has been developed to investigate threedimensional(3D)plasma physics on J-TEXT.This T-SXRI system consists of three sets of SXR arrays.Two sets are newly developed and located on the vacuum chamber wall at toroidal positionsφof 126.4°and 272.6°,respectively,while one set was established previously atφ=65.50.Each set of SXR arrays consists of three arrays viewing the plasma poloidally,and hence can be used separately to obtain SXR images via the tomographic method.The sawtooth precursor oscillations are measured by T-SXRI,and the corresponding images of perturbative SXR signals are successfully reconstructed at these three toroidal positions,hence providing measurement of the 3D structure of precursor oscillations.The observed 3D structure is consistent with the helical structure of the m/n=1/1 mode.The experimental observation confirms that the T-SXRI system is able to observe 3D structures in the J-TEXT plasma.
文摘J-TEXT托卡马克是用来研究热核聚变的实验装置。数据系统是其重要组成部分,由数据采集和数据服务组成。数据采集部分选用PCI总线采集卡,采集程序用LabVIEW编写,运行在Windows操作系统之下。数据服务采用MDSplus软件包,选用Redhat Linux Enterprise为操作系统。本文阐述了该系统的数据流程与实现过程。
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2014GB118000,2014GB106001,2015GB111001,2015GB111002 and 2015GB120003)National Natural Science Foundation of China(Nos.11505069,11275079 and 11405068)
文摘The J-TEXT tokamak has been operated for ten years since its first plasma obtained at the end of 2007. The diagnostics development and main modulation systems, i.e. resonant magnetic perturbation （RMP） systems and massive gas injection （MGI） systems, will be introduced in this paper. Supported by these efforts, J-TEXT has contributed to research on several topics, especially on RMP physics and disruption mitigation. Both experimental and theoretical research show that RMP could lock, suppress or excite the tearing modes, depending on the RMP amplitude, frequency difference between RMP and rational surface rotation, and initial stabilities. The plasma rotation, particle transport and operation region are influenced by the RMP. Utilizing the MGI valves, disruptions have been mitigated with pure He, pure Ne, and a mixture of He and Ar （9：1）. A significant runaway current plateau could be generated with moderate amounts of Ar injection. The RMP has been shown to suppress the generation of runaway current during disruptions.
基金supported by Open Research Program from Key Laboratory of Geospace Environment, Chinese Academy of Sciences
文摘As the basic of a deeper investigation on the turbulent transport, the fluctuation property in the boundary of the newly-reconstructed Joint Texas Experimental Tokamak （J- TEXT） is studied experimentally using the reciprocating Langmuir four-tip probe, which has been built and operated as the primary diagnostic tool in the boundary of J-TEXT tokamak. In this paper, spatial profiles of the plasma-edge parameters are obtained, such as electron temperature, plasma density, plasma potential, poloidal electric field and their fluctuations. The results indicate the existence of a Er ×BT shear layer at the vicinity of last closed flux surface （LCFS）, with the fluctuations suppressed in varying degrees. The turbulence-induced particle and energy fluxes can be calculated by the local plasma parameters above. Convection dominates the cross-field turbulent transport in boundary plasma. Electrostatic fluctuations properties are also studied in detail with the help of numerical analysis. Statistical analysis on density fluctuation shows that, the intermittency can affect the turbulence in the scrape-off layer （SOL）.
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supported by the National Key Research and Development Program of China(Nos.2017YFE0300200 and 2017YFE0300204)the Key Research and Development Program of Hubei Province(No.2021BAA167)National Natural Science Foundation of China(No.51821005)
文摘In order to broaden the range of the plasma parameters and provide experimental conditions for physical research into high-performance plasma,the development of the electron cyclotron resonance heating(ECRH) system for the J-TEXT tokamak was initiated in 2017.For the first stage,the ECRH system operated successfully with one 105 GHz/500 kW/1 s gyrotron in 2019.More than 400 kW electron cyclotron(EC) wave power has been injected into the plasma successfully,raising the core electron temperature to 1.5 keV.In 2022,another 105 GHz/500 kW/1 s gyrotron completed commissioning tests which signifies that the ECRH system could generate an EC wave power of 1 MW in total.Under the support of the ECRH system,various physical experiments have been carried out on J-TEXT.The electron thermal transport in ECRH plasmas has been investigated.When ECRH is turned on,the electron thermal diffusivity significantly increases.The runaway current is elevated when a disruption occurs during ECRH heating.When the injected EC wave power is 400 kW,the conversion efficiency of runaway current increases from 35% to 75%.Fast electron behavior is observed in electron cyclotron current drive(ECCD) plasma by the fast electron bremsstrahlung diagnostic(FEB).The increase in the FEB intensity implies that ECCD could generate fast electrons.A successful startup with a 200 kW ECW is achieved.With the upgrade of the ECRH system,the J-TEXT operational range could be expanded and further relevant research could be conducted.
基金supported by the National Magnetic Confinement Fusion Program of China (Nos. 2015GB120003 and 2014GB108001)
文摘The width of a magnetic island is an important parameter for the quantitative analysis of magnetohydrodynamic-related physics. An electron cyclotron emission radiometer(ECE) is a powerful tool that can be used to obtain this width, which can usually be determined from the flat temperature distribution at the O-point phase or the maxima temperature perturbation. An improved method to estimate the width of a magnetic island is proposed in this paper, and it is independent of calibration. With this method and the existing 24-channel ECE system, the width of a rotation magnetic island can be estimated. Additionally, by filtering the fluctuation ECE signal, the evolution of the magnetic island can be obtained. The results of this method are consistent with those of the integrated magnetic probe signals, which represent the relative change of the magnetic island.
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2015GB111001)National Natural Science Foundation of China(Nos.11305070,11505069)
文摘The limiter target electrostatic measurement system including limiter grounding current sensors and Langmuir probes have been newly developed for the measurement of the limiter target area on the Joint-Texas Experimental tokamak (J-TEXT). Current sensors fixed between graphite limiters and the vacuum vessel walls are used to measure the currents between limiters and vessel wall. Simultaneously, a rectangular poloidal array containing 54 Langmuir probes is embedded in the graphite tiles of limiters for a more localized measurement. Based on this system, the effect of both the plasma’s inherent behavior, including plasma motion and the 2/1 tearing mode, and the electrode biasing on probe and sensor signals have been observed and analyzed in the experiments.
基金supported by National Basic Research Program 973 Program of China(No.2008CB717805)
文摘Joint-TEXT （J-TEXT） is a medium-sized tokamak constructed at Huazhong University of Science and Technology. At present, the poloidal field power supply consists of three subsystem sets, namely Ohmic heating field power supply, vertical field power supply, and horizontal field power supply. The structure and function of the poloidal field （PF） power supply as well as the updated control system of the power supply is described. The new scheme uses the realtime feedback control method for the poloidal field power supply. The experimental results show that the poloidal field energized by poloidal field power supply meets the J-TEXT operational requirement perfectly.
基金National Basic Research Program of China(973 Program)(No.2008CB717805)
文摘J-TEXT, formerly TEXT-U at the University of Texas at Austin in USA, is a medium-sized tokamak at the Huazhong University of Science and Technology. The toroidal field （TF） power supply of this tokamak should provide a current of 160 kA and a flat duration of 500 ms for the toroidal field coils to generate a maximum toroidal field of 3 T at the geometric center of the vaccum vessel. This paper presents a design of a new control system which takes the real-time feedback control option for the TF power supply operation. The system was tested successfully during the commissioning. In the first experimental campaign of J-TEXT, the system effectively controlled the power supply to provide a fiat current up to 92.5 kA and therein the TF produced reached 1.74 T, which enabled the machine to generate the first plasma successfully.
