The plasma optical boundary reconstruction technique based on Hommen's theory is promising for future tokamaks with high parameters. In this work, we conduct detailed analysis and simulation verification to estima...The plasma optical boundary reconstruction technique based on Hommen's theory is promising for future tokamaks with high parameters. In this work, we conduct detailed analysis and simulation verification to estimate the ‘logic loophole' of this technique. The finite-width effect and unpredictable errors reduce the technique's reliability, which leads to this loophole. Based on imaging theory, the photos of a virtual camera are simulated by integrating the assumed luminous intensity of plasma. Based on Hommen's theory, the plasma optical boundary is reconstructed from the photos. Comparing the reconstructed boundary with the one assumed, the logic loophole and its two effects are quantitatively estimated. The finite-width effect is related to the equivalent thickness of the luminous layer, which is generally about 2-4 cm but sometimes larger. The level of unpredictable errors is around 0.65 cm. The technique based on Hommen's theory is generally reliable, but finite-width effect and unpredictable errors have to be taken into consideration in some scenarios. The parameters of HL-2M are applied in this work.展开更多
This paper presents the characteristics of L-mode detachment,together with the behavior of edge turbulent transport and plasma confinement on the HL-2A tokamak.Partially detached and pronounced detached states have be...This paper presents the characteristics of L-mode detachment,together with the behavior of edge turbulent transport and plasma confinement on the HL-2A tokamak.Partially detached and pronounced detached states have been achieved in L-mode plasma.Stored energy was maintained before and after detachment.Edge turbulence and its transport have increased obviously in the partially detached state.In the pronounced detached state,redistribution of the density and temperature profiles due to detachment leads to low amplitude of electron temperature and pressure,as well as very weak edge turbulence and transport.Despite strong plasma radiation in the pronounced detached state,reduced edge turbulent transport contributes to maintaining stored energy in detached L-mode plasma in HL-2A.Different detachment states play an important role in the redistribution of density and temperature profiles,which requires further study.展开更多
A vertical edge Thomson scattering(ETS) diagnostic system on HL-2M tokamak has been designed.The ETS system collects the scattered light from Nd:YAG laser(1064 nm,2 J,30 Hz,15 ns).The laser beam propagates vertically ...A vertical edge Thomson scattering(ETS) diagnostic system on HL-2M tokamak has been designed.The ETS system collects the scattered light from Nd:YAG laser(1064 nm,2 J,30 Hz,15 ns).The laser beam propagates vertically through the plasma region and the polarization is parallel to the toroidal magnetic field.A special designed Galileo-type telescope with long Rayleigh length is applied to focus the laser size and ensure collimation.A group of doubleGaussian collection lenses image the 600 mm vertical scattered region onto rectangular fiber arrays with a spatial resolution of 10 mm.The 2.20 mm × 2.86 mm fiber optic bundle consists of 130 low hydroxyl(OH) 200/220 μm(core/cladding) diameter fibers with numerical aperture NA=0.22,carrying the light to remotely located multi-channel polychromators.Effect of oblique incidence on narrow band filter has been analyzed.The designed electron temperatures range from 5 to 1000 eV and electron densities from 5 × 10^(18) to 1×10^(20) m^(-3).展开更多
基金supported by the Tsinghua University 2021 Doctoral Summer Projectsupported by the National Key R&D Program of China (No. 2018YFE0301102)National Natural Science Foundation of China (Nos. 11875020 and 11875023)。
文摘The plasma optical boundary reconstruction technique based on Hommen's theory is promising for future tokamaks with high parameters. In this work, we conduct detailed analysis and simulation verification to estimate the ‘logic loophole' of this technique. The finite-width effect and unpredictable errors reduce the technique's reliability, which leads to this loophole. Based on imaging theory, the photos of a virtual camera are simulated by integrating the assumed luminous intensity of plasma. Based on Hommen's theory, the plasma optical boundary is reconstructed from the photos. Comparing the reconstructed boundary with the one assumed, the logic loophole and its two effects are quantitatively estimated. The finite-width effect is related to the equivalent thickness of the luminous layer, which is generally about 2-4 cm but sometimes larger. The level of unpredictable errors is around 0.65 cm. The technique based on Hommen's theory is generally reliable, but finite-width effect and unpredictable errors have to be taken into consideration in some scenarios. The parameters of HL-2M are applied in this work.
基金National Key Research and Development Program of China(Nos.2018YFE0303102,2018YFE0309103,2017YFE0300405 and 2017YFE0301203)National Natural Science Foundation of China(Nos.U1867222,11875124,11905051,11805055 and 11875020)Sichuan Youth Science and Technology Innovation Team Project(No.2020JDTD0030)。
文摘This paper presents the characteristics of L-mode detachment,together with the behavior of edge turbulent transport and plasma confinement on the HL-2A tokamak.Partially detached and pronounced detached states have been achieved in L-mode plasma.Stored energy was maintained before and after detachment.Edge turbulence and its transport have increased obviously in the partially detached state.In the pronounced detached state,redistribution of the density and temperature profiles due to detachment leads to low amplitude of electron temperature and pressure,as well as very weak edge turbulence and transport.Despite strong plasma radiation in the pronounced detached state,reduced edge turbulent transport contributes to maintaining stored energy in detached L-mode plasma in HL-2A.Different detachment states play an important role in the redistribution of density and temperature profiles,which requires further study.
基金supported by the National Key Research and Development Program of China (Nos. 2019YFE0302002, 2017YFE0301203 and 2017YFE0301202)National Natural Science Foundation of China (No. 12175055)。
文摘A vertical edge Thomson scattering(ETS) diagnostic system on HL-2M tokamak has been designed.The ETS system collects the scattered light from Nd:YAG laser(1064 nm,2 J,30 Hz,15 ns).The laser beam propagates vertically through the plasma region and the polarization is parallel to the toroidal magnetic field.A special designed Galileo-type telescope with long Rayleigh length is applied to focus the laser size and ensure collimation.A group of doubleGaussian collection lenses image the 600 mm vertical scattered region onto rectangular fiber arrays with a spatial resolution of 10 mm.The 2.20 mm × 2.86 mm fiber optic bundle consists of 130 low hydroxyl(OH) 200/220 μm(core/cladding) diameter fibers with numerical aperture NA=0.22,carrying the light to remotely located multi-channel polychromators.Effect of oblique incidence on narrow band filter has been analyzed.The designed electron temperatures range from 5 to 1000 eV and electron densities from 5 × 10^(18) to 1×10^(20) m^(-3).
