Core and edge turbulences were measured by Langmuir probe arrays in the KT-5C tokamak plasma.The radial wavenumber spectra show a quasimode like structure which results in a net radial outward propagation of the turbu...Core and edge turbulences were measured by Langmuir probe arrays in the KT-5C tokamak plasma.The radial wavenumber spectra show a quasimode like structure which results in a net radial outward propagation of the turbulent fluctuations.The measured fluctuation levels and wave action fluxes are in good agreement with model predictions by Mattor et al.,suggesting that drift wave propagation could be a source of edge turbulence.展开更多
A low-frequency(f<2 kHz)potential structure(LFPS)is observed in a linear magnetic plasma device using Langmuir probe arrays.The center frequency of this structure is near zero.This structure has azimuthal and axial...A low-frequency(f<2 kHz)potential structure(LFPS)is observed in a linear magnetic plasma device using Langmuir probe arrays.The center frequency of this structure is near zero.This structure has azimuthal and axial symmetries while with a finite radial wavenumber.The complete 3D spectra features of this structure have been identified to have the characteristics expected for zonal flows.展开更多
Power spectrum and the probability distribution function(PDF)of the turbulence-induced particle fluxΓin the velocity shear layer of the HT-6M edge region have been measured and analysed.Three regions of frequency dep...Power spectrum and the probability distribution function(PDF)of the turbulence-induced particle fluxΓin the velocity shear layer of the HT-6M edge region have been measured and analysed.Three regions of frequency dependence(f0,f-1,f-4)have been observed in the spectrum of the flux.The PDF of the flux displays aΓ-1 scaling over one decade inΓ.Using the rescaled-range statistical technique,we find that the degree of the self-similarity(Hurst exponent)of the particle flux in the measured region ranges from 0.64 to 0.83.All of these results may mean that the plasma transport is in a state characterized by the self-organized criticality.展开更多
High spatial resolution measurements of the electrostatic Reynolds stress,radial electric field and poloidal phase velocity of fluctuations in the edge region of the HT-6M tokamak are carried out.The Reynolds stress s...High spatial resolution measurements of the electrostatic Reynolds stress,radial electric field and poloidal phase velocity of fluctuations in the edge region of the HT-6M tokamak are carried out.The Reynolds stress shows a radial gradient in proximity to the poloidal velocity shear.A comparison of the profiles between the Reynolds stress gradient and the poloidal velocity damping reveals some similarity in their magnitude and radial structure.These facts suggest that the turbulence-induced Reynolds stress may play a significant role in generating the poloidal flow in the plasma edge region.展开更多
Time-resolved Thomson scattering was successfully performed to diagnose the parameters(ZTe,Ue and Ui)of laser-produced gold plasma.The results show that the collisionless dynamic form factor is accurate enough to be u...Time-resolved Thomson scattering was successfully performed to diagnose the parameters(ZTe,Ue and Ui)of laser-produced gold plasma.The results show that the collisionless dynamic form factor is accurate enough to be used for reducing the plasma parameters from the experimental data.展开更多
Time and space resolved measurements of the radial electric field(Er)have been conducted during the electrode biasing experiments on the KT-5C tokamak.The suppression of the turbulent transport with the change of Er i...Time and space resolved measurements of the radial electric field(Er)have been conducted during the electrode biasing experiments on the KT-5C tokamak.The suppression of the turbulent transport with the change of Er induced by the biased electrode is observed.It is found that the poloidal flow contributes to the main part of the Er,and the change of the poloidal flow has a lead of about 20μs to the formation of Er.These observations suggest that a radial current,responding to an induced voltage on the electrode,drives a poloidal flow which in turn drives the radial electric field.展开更多
Power spectra of electron density and floating potential fluctuations in the velocity shear layer of the HT-6M edge region have been measured and analysed.All the spectra have three distinct frequency regions with the...Power spectra of electron density and floating potential fluctuations in the velocity shear layer of the HT-6M edge region have been measured and analysed.All the spectra have three distinct frequency regions with the spectral decay indices typical of self-organized criticality systems(0,-1 and-4)when Doppler shift effects induced by the plasma E x B flow velocity have been taken into account.These results are consistent with the predictions of the self-organized criticality models,which may be an indication of edge plasma turbulence in the HT-6M tokamak evolving into a critical state independent of local plasma parameters.展开更多
Hydrogen-free diamond-like carbon (DLC) films with the optical band gaps of 2.0-2.7 e V and the microhardness of 40-55 GPa are deposited by femtosecond KrF laser pulses. The film microstructure of nanometer spheroid i...Hydrogen-free diamond-like carbon (DLC) films with the optical band gaps of 2.0-2.7 e V and the microhardness of 40-55 GPa are deposited by femtosecond KrF laser pulses. The film microstructure of nanometer spheroid is observed. The filrn microhardness is improved with the increase of ion kinetic energy of plasma plume from 300 to 600 eV. The characteristics of DLC film deposition with fs pulses is discussed.展开更多
Features of a low frequency ion mode were observed together with the electron drift wave type fluctuations by a Langmuir probe array in the bulk plasma inside the velocity shear layer in the KT-5C tokamak.The measured...Features of a low frequency ion mode were observed together with the electron drift wave type fluctuations by a Langmuir probe array in the bulk plasma inside the velocity shear layer in the KT-5C tokamak.The measured ion mode wavenumber,scaling of the ion mode with chord-averaged density,and the estimatedηi value suggest that the observed ion mode may be the theoretically predictedηi mode driven by ion temperature gradient.展开更多
It is found on KT-5C tokamak that an edge fluctuation mode can be excited by using a pair of floating Langmuir probes.This mode is propagating along the magnetic field with its amplitude decreasing drastically when it...It is found on KT-5C tokamak that an edge fluctuation mode can be excited by using a pair of floating Langmuir probes.This mode is propagating along the magnetic field with its amplitude decreasing drastically when it is off the magnetic field line.Preliminary feedback experiments show that the broadband edge turbulence can be reduced or enhanced depending upon the phase shift of the feedback network.展开更多
In this paper,a controlled laboratory experiment to investigate the response properties of reflec-tometry to the density fluctuations is presented.The reflectometer signal is observed to be highly spatially localized ...In this paper,a controlled laboratory experiment to investigate the response properties of reflec-tometry to the density fluctuations is presented.The reflectometer signal is observed to be highly spatially localized in the plasma.The quantitative measurement has demonstrated that the signal originates about one free space wavelength of the probe•wave in front of the critical layer and this position is independent of the fluctuation wavenumber.It is also found that the sensitivity of transverse response to wavenumbers is different from that of longitudinal response.展开更多
A new feature in the Thomson scattering spectrum is observed from a laser-produced aluminium plasma, which may be the Thomson scattering off entropy waves in the plasma. Such a feature is only observable when the ener...A new feature in the Thomson scattering spectrum is observed from a laser-produced aluminium plasma, which may be the Thomson scattering off entropy waves in the plasma. Such a feature is only observable when the energy of the heater beam is low enough.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos.19675036,19635020the Doctoral Training Foundation of National Education Commission of China and Chinese Academy of Sciences.
文摘Core and edge turbulences were measured by Langmuir probe arrays in the KT-5C tokamak plasma.The radial wavenumber spectra show a quasimode like structure which results in a net radial outward propagation of the turbulent fluctuations.The measured fluctuation levels and wave action fluxes are in good agreement with model predictions by Mattor et al.,suggesting that drift wave propagation could be a source of edge turbulence.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10875124 and 10605025the National Basic Research Program of China under Grant No 2008CB717800+2 种基金Research Fund for the Doctoral Program of Higher Education of China under Grant No 20060358059the ITER domestic program of China under Grant No 2010GB107000the Knowledge Innovation Program of Chinese Academy of Sciences under Grant No kjcx-yw-n28.
文摘A low-frequency(f<2 kHz)potential structure(LFPS)is observed in a linear magnetic plasma device using Langmuir probe arrays.The center frequency of this structure is near zero.This structure has azimuthal and axial symmetries while with a finite radial wavenumber.The complete 3D spectra features of this structure have been identified to have the characteristics expected for zonal flows.
基金Supported by the National Natural Science Foundation of China under Grants Nos.19675036the Research Fund for the Doctoral Program of Higher Education(1999035809).
文摘Power spectrum and the probability distribution function(PDF)of the turbulence-induced particle fluxΓin the velocity shear layer of the HT-6M edge region have been measured and analysed.Three regions of frequency dependence(f0,f-1,f-4)have been observed in the spectrum of the flux.The PDF of the flux displays aΓ-1 scaling over one decade inΓ.Using the rescaled-range statistical technique,we find that the degree of the self-similarity(Hurst exponent)of the particle flux in the measured region ranges from 0.64 to 0.83.All of these results may mean that the plasma transport is in a state characterized by the self-organized criticality.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19675036 and 19635020the Research Fund for the Doctoral Program of Higher Education。
文摘High spatial resolution measurements of the electrostatic Reynolds stress,radial electric field and poloidal phase velocity of fluctuations in the edge region of the HT-6M tokamak are carried out.The Reynolds stress shows a radial gradient in proximity to the poloidal velocity shear.A comparison of the profiles between the Reynolds stress gradient and the poloidal velocity damping reveals some similarity in their magnitude and radial structure.These facts suggest that the turbulence-induced Reynolds stress may play a significant role in generating the poloidal flow in the plasma edge region.
基金Supported by the National High Technology Programs on Inertial Confinement Fusion(No.416-3-1.2)the National Natural Science Foundation of China under Grant No.19905009,Foundation of the Laboratory for Laser Fusion.
文摘Time-resolved Thomson scattering was successfully performed to diagnose the parameters(ZTe,Ue and Ui)of laser-produced gold plasma.The results show that the collisionless dynamic form factor is accurate enough to be used for reducing the plasma parameters from the experimental data.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19635020,19675036,19775046the Chinese Academy of Sciences,and the National Doctoral Training Foundation under Grant Nos.9535806,9803810.
文摘Time and space resolved measurements of the radial electric field(Er)have been conducted during the electrode biasing experiments on the KT-5C tokamak.The suppression of the turbulent transport with the change of Er induced by the biased electrode is observed.It is found that the poloidal flow contributes to the main part of the Er,and the change of the poloidal flow has a lead of about 20μs to the formation of Er.These observations suggest that a radial current,responding to an induced voltage on the electrode,drives a poloidal flow which in turn drives the radial electric field.
基金Sponsored by the National Natural Science Foundation of China under Grant Nos.19675036 and 19635020the Research Fund for the Doctoral Programme of Higher Education under Grant No.1999035809the Chinese Academy of China.
文摘Power spectra of electron density and floating potential fluctuations in the velocity shear layer of the HT-6M edge region have been measured and analysed.All the spectra have three distinct frequency regions with the spectral decay indices typical of self-organized criticality systems(0,-1 and-4)when Doppler shift effects induced by the plasma E x B flow velocity have been taken into account.These results are consistent with the predictions of the self-organized criticality models,which may be an indication of edge plasma turbulence in the HT-6M tokamak evolving into a critical state independent of local plasma parameters.
基金Supported by the National Natural Science Foundation of China under Grant No.19835030.
文摘Hydrogen-free diamond-like carbon (DLC) films with the optical band gaps of 2.0-2.7 e V and the microhardness of 40-55 GPa are deposited by femtosecond KrF laser pulses. The film microstructure of nanometer spheroid is observed. The filrn microhardness is improved with the increase of ion kinetic energy of plasma plume from 300 to 600 eV. The characteristics of DLC film deposition with fs pulses is discussed.
基金Supported by the National Natural Science Foundation of China under Grant No.19275041the Doctoral Training Foundation of National Education Commission of China,and the Chinese Academy of Sciences.
文摘Features of a low frequency ion mode were observed together with the electron drift wave type fluctuations by a Langmuir probe array in the bulk plasma inside the velocity shear layer in the KT-5C tokamak.The measured ion mode wavenumber,scaling of the ion mode with chord-averaged density,and the estimatedηi value suggest that the observed ion mode may be the theoretically predictedηi mode driven by ion temperature gradient.
基金Supported by the Fund of the Chinese Academy of Sciences,and the National High Technology Program of China.
文摘It is found on KT-5C tokamak that an edge fluctuation mode can be excited by using a pair of floating Langmuir probes.This mode is propagating along the magnetic field with its amplitude decreasing drastically when it is off the magnetic field line.Preliminary feedback experiments show that the broadband edge turbulence can be reduced or enhanced depending upon the phase shift of the feedback network.
基金Supported by the National Natural Science Foundation of Chinathe Doctoral Training Foundation of National Education Commission and Chinese Academy of Sciences.
文摘In this paper,a controlled laboratory experiment to investigate the response properties of reflec-tometry to the density fluctuations is presented.The reflectometer signal is observed to be highly spatially localized in the plasma.The quantitative measurement has demonstrated that the signal originates about one free space wavelength of the probe•wave in front of the critical layer and this position is independent of the fluctuation wavenumber.It is also found that the sensitivity of transverse response to wavenumbers is different from that of longitudinal response.
基金Supported by the National High Technology Programme on Inertial Confinement Fusion(416-3-1.2)in part by the National Natural Science Foundation of China under Grant No.19905009。
文摘A new feature in the Thomson scattering spectrum is observed from a laser-produced aluminium plasma, which may be the Thomson scattering off entropy waves in the plasma. Such a feature is only observable when the energy of the heater beam is low enough.