The Vacuum Vessel(VV) system is an essential component of Keda Torus for experiment(KTX),and various scenarios might take place on it.The VV's supports should be adequately strong to stand against various loads on...The Vacuum Vessel(VV) system is an essential component of Keda Torus for experiment(KTX),and various scenarios might take place on it.The VV's supports should be adequately strong to stand against various loads on VV,which might happen in extreme scenarios.Therefore,the design of VV supports is verified in a single extreme scenario and is subsequently optimized in this report.The numerical simulation based on Finite Element theory is performed as the major method for analysis and optimization.The electromagnetic force in previous analyses serves as the load for the mechanical analyses of supports.During the optimization,the stresses of the W supports decrease remarkably after introducing cotters.Finally,the optimum design has been worked out.It satisfies the requirements regarding the strength and convenience in assembly.展开更多
The design of the poloidal field(PF) system includes the ohmic heating field system and the equilibrium(EQ) field system, and is the basis for the design of a magnetic confinement fusion device. A coupling between the...The design of the poloidal field(PF) system includes the ohmic heating field system and the equilibrium(EQ) field system, and is the basis for the design of a magnetic confinement fusion device. A coupling between the poloidal and plasma currents, especially the eddy current in the stabilizing shell, yields design difficulties. The effects of the eddy current in the stabilizing shell on the poloidal magnetic field also cannot be ignored. A new PF system design is thus proposed.By using a low-μ material(μ?=?0.001, ε?=?1) instead of a conductive shell, an electromagnetic model is established that can provide a continuous eddy current distribution on the conductive shell. In this model, a 3 D time-domain problem with shells translates into a 2 D magnetostatic problem, and the accuracy of the calculation is improved. Based on these current distributions, we design the PF system and analyze how the EQ coils and conductive shell affect the plasma EQ when the plasma ramps up. To meet the mainframe design requirements and achieve an efficient power-supply design, the position and connection of the poloidal coils are optimized further.展开更多
KTX(Keda Torus for eXperiment)is a new reversed field pinch device.The KTX plasma control system(PCS)can provide real-time,stable,flexible plasma control which is designed by ASIPP(Institute of Plasma Physics,Chinese ...KTX(Keda Torus for eXperiment)is a new reversed field pinch device.The KTX plasma control system(PCS)can provide real-time,stable,flexible plasma control which is designed by ASIPP(Institute of Plasma Physics,Chinese Academy of Sciences),based on the Linux cluster system and EPICS(Experimental Physics and Industrial Control System)framework,and developed from DIII-D(Doublet III-D)PCS.The control of the equilibrium field in KTX uses a PID(Proportional-Integral-Derivative)feedback controller.The control of the gas injection is an open loop control.The plasma control simulation system is one part of the plasma control system,which is used to test the plasma control algorithm if it is revised and updated.The KTX PCS has been successfully tested using HT-7(Hefei Torus 7)experiment data in simulation mode.In the next phase,an error field feedback control and KTX simulator will be added to the KTX PCS,and the KTX PCS will be applied in experiments in the future.展开更多
The KTX device is a reversed field pinch(RFP)device currently under construction.Its maximum plasma current is designed as 1 MA with a discharge time longer than 100 ms.Its major radius is 1.4 m and its minor radius i...The KTX device is a reversed field pinch(RFP)device currently under construction.Its maximum plasma current is designed as 1 MA with a discharge time longer than 100 ms.Its major radius is 1.4 m and its minor radius is 0.55 m.One of the most important problems in the magnet system design is how to reduce the TF magnetic field ripple and error field.A new wedgeshaped TF coil is put forward for the KTX device and its electromagnetic properties are compared with those of rectangular-shaped TF coils.The error field Bn/Btof wedge-shaped TF coils with6.4 degrees is about 6%as compared with 8%in the case of a rectangular-shaped TF coil.Besides,the wedge-shaped TF coils have a lower magnetic field ripple at the edge of the plasma region,which is smaller than 7.5%at R=1.83 m and 2%at R=1.07 m.This means that the tokamak operation mode may be feasible for this device when the plasma area becomes smaller,because the maximum ripple in the plasma area of the tokamak model is always required to be smaller than 0.4%.Detailed analysis of the results shows that the structure of the wedged-shape TF coil is reliable.It can serve as a reference for TF coil design of small aspect ratio RFPs or similar torus devices.展开更多
The Vacuum Vessel(VV) system is a vital component of Keda Torus for experiment(KTX).Various accidental scenarios might occur on the VV.In this report,an extreme scenario is assumed and studied:plasma accidental termin...The Vacuum Vessel(VV) system is a vital component of Keda Torus for experiment(KTX).Various accidental scenarios might occur on the VV.In this report,an extreme scenario is assumed and studied:plasma accidental termination during the flat-top stage.Numerical simulations based on finite element are performed as the major tool for analyses.The detailed distributions of eddy and the reaction forces on VV are extracted,and the total eddy current and the maximum reaction force due to electromagnetic load are figured out.In addition,according to the results,the VV can be approximately regarded as a centrally symmetric structure,even though its ports distribution is asymmetric.展开更多
Radial equilibrium of the KTX plasma column is maintained by the vertical field which is produced by the equilibrium field coils.The equilibrium is also affected by the eddy current,which is generated by the coupling ...Radial equilibrium of the KTX plasma column is maintained by the vertical field which is produced by the equilibrium field coils.The equilibrium is also affected by the eddy current,which is generated by the coupling of copper shell,plasma and poloidal field coils.An equivalent circuit model is developed to analyze the dynamic performance of equilibrium field coils,without auxiliary power input to equilibrium field coils and passive conductors.Considering the coupling of poloidal field coils,copper shell and plasma,the evolution of spatial distribution of the eddy current density on the copper shell is estimated by finite element to analyze the effect of shell to balance.The simulation results show that the copper shell and equilibrium field coils can provide enough vertical field to balance 1 MA plasma current in phase 1 of a KTX discharge.Auxiliary power supply on the EQ coils is necessary to control the horizontal displacement of KTX due to the finite resistance effect of the shell.展开更多
A 10-channel Hα diagnostic system has been designed with the rapid response rate of 300 kHz, spatial resolution of about 40 mm, and overlap between adjacent channels of about 3%, and it has been implemented successfu...A 10-channel Hα diagnostic system has been designed with the rapid response rate of 300 kHz, spatial resolution of about 40 mm, and overlap between adjacent channels of about 3%, and it has been implemented successfully on Keda Torus eXperiment(KTX), a newly constructed, reversed field pinch(RFP) experimental device at the University of Science and Technology of China(USTC). This diagnostic system is a very important tool for the initial KTX operations. It is compact,with an aperture slit replacing the traditional optical lens system. A flexural interference filter is designed to prevent the center wavelength from shifting too much as the increase of angle from vertical incidence. To eliminate the stray light,the interior of the system is covered with the black aluminum foil having a very high absorptivity. Using the Hαemission data, together with the profiles of electron temperature and density obtained from the Langmuir probe, the neutral density profiles have been calculated for KTX plasmas. The rapid response rate and good spatial resolution of this Hαdiagnostic system will be beneficial for many studies in RFP plasma physics.展开更多
文摘The Vacuum Vessel(VV) system is an essential component of Keda Torus for experiment(KTX),and various scenarios might take place on it.The VV's supports should be adequately strong to stand against various loads on VV,which might happen in extreme scenarios.Therefore,the design of VV supports is verified in a single extreme scenario and is subsequently optimized in this report.The numerical simulation based on Finite Element theory is performed as the major method for analysis and optimization.The electromagnetic force in previous analyses serves as the load for the mechanical analyses of supports.During the optimization,the stresses of the W supports decrease remarkably after introducing cotters.Finally,the optimum design has been worked out.It satisfies the requirements regarding the strength and convenience in assembly.
基金supported by the National Magnetic Confinement Fusion Research Program of China (2011GB106000)
文摘The design of the poloidal field(PF) system includes the ohmic heating field system and the equilibrium(EQ) field system, and is the basis for the design of a magnetic confinement fusion device. A coupling between the poloidal and plasma currents, especially the eddy current in the stabilizing shell, yields design difficulties. The effects of the eddy current in the stabilizing shell on the poloidal magnetic field also cannot be ignored. A new PF system design is thus proposed.By using a low-μ material(μ?=?0.001, ε?=?1) instead of a conductive shell, an electromagnetic model is established that can provide a continuous eddy current distribution on the conductive shell. In this model, a 3 D time-domain problem with shells translates into a 2 D magnetostatic problem, and the accuracy of the calculation is improved. Based on these current distributions, we design the PF system and analyze how the EQ coils and conductive shell affect the plasma EQ when the plasma ramps up. To meet the mainframe design requirements and achieve an efficient power-supply design, the position and connection of the poloidal coils are optimized further.
基金supported by the External Cooperation Program of BIC,Chinese Academy of Sciences(No.GJHZ201303)the National Magnetic Confinement Fusion Research Program of China(Nos.2014GB10300,2012GB105000 and 2011GB10600)+1 种基金National Natural Science Foundation of China(No.11205200)the Anhui Provincial Science Foundation for Outstanding Young Talent of China(No.2012SQRL265)
文摘KTX(Keda Torus for eXperiment)is a new reversed field pinch device.The KTX plasma control system(PCS)can provide real-time,stable,flexible plasma control which is designed by ASIPP(Institute of Plasma Physics,Chinese Academy of Sciences),based on the Linux cluster system and EPICS(Experimental Physics and Industrial Control System)framework,and developed from DIII-D(Doublet III-D)PCS.The control of the equilibrium field in KTX uses a PID(Proportional-Integral-Derivative)feedback controller.The control of the gas injection is an open loop control.The plasma control simulation system is one part of the plasma control system,which is used to test the plasma control algorithm if it is revised and updated.The KTX PCS has been successfully tested using HT-7(Hefei Torus 7)experiment data in simulation mode.In the next phase,an error field feedback control and KTX simulator will be added to the KTX PCS,and the KTX PCS will be applied in experiments in the future.
基金supported by the National ITER Special Support for R&D on Science and Technology for ITER,"Research on Reversed Field Pinch Magnetic Confinement Configuration",CN Schedule Task(No.2011GB106000)
文摘The KTX device is a reversed field pinch(RFP)device currently under construction.Its maximum plasma current is designed as 1 MA with a discharge time longer than 100 ms.Its major radius is 1.4 m and its minor radius is 0.55 m.One of the most important problems in the magnet system design is how to reduce the TF magnetic field ripple and error field.A new wedgeshaped TF coil is put forward for the KTX device and its electromagnetic properties are compared with those of rectangular-shaped TF coils.The error field Bn/Btof wedge-shaped TF coils with6.4 degrees is about 6%as compared with 8%in the case of a rectangular-shaped TF coil.Besides,the wedge-shaped TF coils have a lower magnetic field ripple at the edge of the plasma region,which is smaller than 7.5%at R=1.83 m and 2%at R=1.07 m.This means that the tokamak operation mode may be feasible for this device when the plasma area becomes smaller,because the maximum ripple in the plasma area of the tokamak model is always required to be smaller than 0.4%.Detailed analysis of the results shows that the structure of the wedged-shape TF coil is reliable.It can serve as a reference for TF coil design of small aspect ratio RFPs or similar torus devices.
文摘The Vacuum Vessel(VV) system is a vital component of Keda Torus for experiment(KTX).Various accidental scenarios might occur on the VV.In this report,an extreme scenario is assumed and studied:plasma accidental termination during the flat-top stage.Numerical simulations based on finite element are performed as the major tool for analyses.The detailed distributions of eddy and the reaction forces on VV are extracted,and the total eddy current and the maximum reaction force due to electromagnetic load are figured out.In addition,according to the results,the VV can be approximately regarded as a centrally symmetric structure,even though its ports distribution is asymmetric.
基金supported by the Ministry of Science and Technology of China(No.2011GB106000)
文摘Radial equilibrium of the KTX plasma column is maintained by the vertical field which is produced by the equilibrium field coils.The equilibrium is also affected by the eddy current,which is generated by the coupling of copper shell,plasma and poloidal field coils.An equivalent circuit model is developed to analyze the dynamic performance of equilibrium field coils,without auxiliary power input to equilibrium field coils and passive conductors.Considering the coupling of poloidal field coils,copper shell and plasma,the evolution of spatial distribution of the eddy current density on the copper shell is estimated by finite element to analyze the effect of shell to balance.The simulation results show that the copper shell and equilibrium field coils can provide enough vertical field to balance 1 MA plasma current in phase 1 of a KTX discharge.Auxiliary power supply on the EQ coils is necessary to control the horizontal displacement of KTX due to the finite resistance effect of the shell.
基金Project supported by the National Magnetic Confinement Fusion Science Program of China(Grant No.2017YFE0301700)the National Natural Science Foundation of China(Grant No.11635008)
文摘A 10-channel Hα diagnostic system has been designed with the rapid response rate of 300 kHz, spatial resolution of about 40 mm, and overlap between adjacent channels of about 3%, and it has been implemented successfully on Keda Torus eXperiment(KTX), a newly constructed, reversed field pinch(RFP) experimental device at the University of Science and Technology of China(USTC). This diagnostic system is a very important tool for the initial KTX operations. It is compact,with an aperture slit replacing the traditional optical lens system. A flexural interference filter is designed to prevent the center wavelength from shifting too much as the increase of angle from vertical incidence. To eliminate the stray light,the interior of the system is covered with the black aluminum foil having a very high absorptivity. Using the Hαemission data, together with the profiles of electron temperature and density obtained from the Langmuir probe, the neutral density profiles have been calculated for KTX plasmas. The rapid response rate and good spatial resolution of this Hαdiagnostic system will be beneficial for many studies in RFP plasma physics.
