An outline of the complete design of the cryogenic system, including the detection of quench signals, the processing flow after a quench and the concrete measures of pressure release for EAST is described in this pape...An outline of the complete design of the cryogenic system, including the detection of quench signals, the processing flow after a quench and the concrete measures of pressure release for EAST is described in this paper. The hardware and software configurations on DeltaV DCS are illustrated in detail. The results of quench protection testing in cooling experiments are also analyzed.展开更多
The Experiments of Modulated Toroidal Current were done on the HT-6M tokamak and HT-7 superconducting tokamak. The toroidal current was modulated by programming the Ohmic heating field. Modulation of the plasma curren...The Experiments of Modulated Toroidal Current were done on the HT-6M tokamak and HT-7 superconducting tokamak. The toroidal current was modulated by programming the Ohmic heating field. Modulation of the plasma current has been used successfully to suppress MHD activity in discharges near the density limit where large MHD m = 2 tearing modes were suppressed by sufficiently large plasma current oscillations. The improved Ohmic confinement phase was observed during modulating toroidal current (MTC) on the Hefei Tokamak-6M (HT-6M) and Hefei superconducting Tokamak-7 (HT-7). A toroidal frequency-modulated current, induced by a modulated loop voltage, was added on the plasma equilibrium current. The ratio of A.C. amplitude of plasma current to the main plasma current Ip/Ip is about 12% ~ 30%. The different formats of the frequency-modulated toroidal current were compared.展开更多
Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity manage...Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity management, and the coupling of multiple heating and current drive power. A discharge with a lower single null divertor configuration was maintained for 103 s at a plasma current of 0.4 MA, q95 ≈7.0, a peak electron temperature of 〉4.5 keV, and a central density ne（0）-2.5×10^19 m^-3. The plasma current was nearly non-inductive （Vloop 〈0.05 V, poloidal beta - 0.9） driven by a combination of 0.6 MW lower hybrid wave at 2.45 GHz, 1.4 MW lower hybrid wave at 4.6 GHz, 0.5 MW electron cyclotron heating at 140 GHz, and 0.4 MW modulated neutral deuterium beam injected at 60 kV. This progress demonstrated strong synergy of electron cyclotron and lower hybrid electron heating, current drive, and energy confinement of stationary plasma on EAST. It further introduced an example of integrated ＂hybrid＂ operating scenario of interest to ITER and CFETR.展开更多
The superconducting toroidal field （TF） plays an important role in a superconducting tokamak, whose power supply was developed based on the feedback control principle. In this paper, superconducting tokamaks in diff...The superconducting toroidal field （TF） plays an important role in a superconducting tokamak, whose power supply was developed based on the feedback control principle. In this paper, superconducting tokamaks in different countries are described, and the TF power supply of the International Thermonuclear Experimental Reactor （ITER） is taken as an example to study the current-sharing characteristics in the current-stabilized stage. Firstly, the mathematical model of the TF power supply is established, and then the 3-loop control method is put forward for achieving the stability and reliability of current-stabilization and current-sharing. Furthermore, further studies indicate that the current-sharing controller has no influence on the current-stabilized control, and current-stabilizing and current-sharing can be realized at the same time. All the work done provides valuable references for the current-sharing design of the TF power supply for a superconducting tokamak, and all these studies lay a solid foundation for developing superconducting tokamaks.展开更多
Due to the complicated constitution and high precision requirements of the EAST superconducting tokamak, a meticulous assembling procedure and measurement scheme must be established. The big size and mass of the EAST ...Due to the complicated constitution and high precision requirements of the EAST superconducting tokamak, a meticulous assembling procedure and measurement scheme must be established. The big size and mass of the EAST machine＇s components and complicated configuration with tight installation tolerances call for a highly careful assembling procedure. The assembling procedure consists of three main sub-procedures for the assembling of the base, of the tori of the VV, the vacuum vessel TS and the TF, and of the peripheral parts respectively. Before the assembly, a reference framework has been set up by means of an industrial measurement system with reference fiducial targets fixed on the wall of the test hall. In this paper, the assembling procedure is described in detail, the survey control system of the assembly is discussed, and progress in the assembly work is also reported.展开更多
Plasma control on high-β_N steady-state operation for JT-60 superconductingmodification is discussed. Accessibility to high-β_N exceeding the free-boundary limit isinvestigated with the stabilising wall of reduced-a...Plasma control on high-β_N steady-state operation for JT-60 superconductingmodification is discussed. Accessibility to high-β_N exceeding the free-boundary limit isinvestigated with the stabilising wall of reduced-activated ferritic steel and the active feedbackcontrol of the ill-vessel non-axisymmetric field coils. Taking the merit of superconducting magnet,advanced plasma control for steady-state high performance operation could be expected.展开更多
基金supported by National Meg-Science Engineering Project of Chinese Government (No.10575105)
文摘An outline of the complete design of the cryogenic system, including the detection of quench signals, the processing flow after a quench and the concrete measures of pressure release for EAST is described in this paper. The hardware and software configurations on DeltaV DCS are illustrated in detail. The results of quench protection testing in cooling experiments are also analyzed.
基金The project supported by the National Nature Science Foundation of China (No.10075049 and No.10275068)
文摘The Experiments of Modulated Toroidal Current were done on the HT-6M tokamak and HT-7 superconducting tokamak. The toroidal current was modulated by programming the Ohmic heating field. Modulation of the plasma current has been used successfully to suppress MHD activity in discharges near the density limit where large MHD m = 2 tearing modes were suppressed by sufficiently large plasma current oscillations. The improved Ohmic confinement phase was observed during modulating toroidal current (MTC) on the Hefei Tokamak-6M (HT-6M) and Hefei superconducting Tokamak-7 (HT-7). A toroidal frequency-modulated current, induced by a modulated loop voltage, was added on the plasma equilibrium current. The ratio of A.C. amplitude of plasma current to the main plasma current Ip/Ip is about 12% ~ 30%. The different formats of the frequency-modulated toroidal current were compared.
基金supported by the National Magnetic Confinement Fusion Science Foundation of China(Nos.2015GB102000 and 2014GB103000)
文摘Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity management, and the coupling of multiple heating and current drive power. A discharge with a lower single null divertor configuration was maintained for 103 s at a plasma current of 0.4 MA, q95 ≈7.0, a peak electron temperature of 〉4.5 keV, and a central density ne（0）-2.5×10^19 m^-3. The plasma current was nearly non-inductive （Vloop 〈0.05 V, poloidal beta - 0.9） driven by a combination of 0.6 MW lower hybrid wave at 2.45 GHz, 1.4 MW lower hybrid wave at 4.6 GHz, 0.5 MW electron cyclotron heating at 140 GHz, and 0.4 MW modulated neutral deuterium beam injected at 60 kV. This progress demonstrated strong synergy of electron cyclotron and lower hybrid electron heating, current drive, and energy confinement of stationary plasma on EAST. It further introduced an example of integrated ＂hybrid＂ operating scenario of interest to ITER and CFETR.
基金supported by the National Basic Research Program of China(973Program)(No.2007ID200)the Special Fund of Talent Development of Anhui Province(No.2009Z056)the Research Fund for the Doctoral Program of Anhui University of Architecture(No.K02425)
文摘The superconducting toroidal field （TF） plays an important role in a superconducting tokamak, whose power supply was developed based on the feedback control principle. In this paper, superconducting tokamaks in different countries are described, and the TF power supply of the International Thermonuclear Experimental Reactor （ITER） is taken as an example to study the current-sharing characteristics in the current-stabilized stage. Firstly, the mathematical model of the TF power supply is established, and then the 3-loop control method is put forward for achieving the stability and reliability of current-stabilization and current-sharing. Furthermore, further studies indicate that the current-sharing controller has no influence on the current-stabilized control, and current-stabilizing and current-sharing can be realized at the same time. All the work done provides valuable references for the current-sharing design of the TF power supply for a superconducting tokamak, and all these studies lay a solid foundation for developing superconducting tokamaks.
基金The project supported by the National Meg-science Engineering Project of Chinese Government and the Chinese Academy of Sciences (SYKXD04)
文摘Due to the complicated constitution and high precision requirements of the EAST superconducting tokamak, a meticulous assembling procedure and measurement scheme must be established. The big size and mass of the EAST machine＇s components and complicated configuration with tight installation tolerances call for a highly careful assembling procedure. The assembling procedure consists of three main sub-procedures for the assembling of the base, of the tori of the VV, the vacuum vessel TS and the TF, and of the peripheral parts respectively. Before the assembly, a reference framework has been set up by means of an industrial measurement system with reference fiducial targets fixed on the wall of the test hall. In this paper, the assembling procedure is described in detail, the survey control system of the assembly is discussed, and progress in the assembly work is also reported.
文摘Plasma control on high-β_N steady-state operation for JT-60 superconductingmodification is discussed. Accessibility to high-β_N exceeding the free-boundary limit isinvestigated with the stabilising wall of reduced-activated ferritic steel and the active feedbackcontrol of the ill-vessel non-axisymmetric field coils. Taking the merit of superconducting magnet,advanced plasma control for steady-state high performance operation could be expected.
