An edge Lyman-alpha-based beam emission spectroscopy(LyBES)diagnostic,using a heating NBI(neutral beam injection)system,is currently under development on the HL-2A tokamak.The 20-channel edge LyBES,which is intended t...An edge Lyman-alpha-based beam emission spectroscopy(LyBES)diagnostic,using a heating NBI(neutral beam injection)system,is currently under development on the HL-2A tokamak.The 20-channel edge LyBES,which is intended to measure the density fluctuation in plasma edge(from R=1960 mm to R=2026 mm)with an improved spatial resolution of 3.3 mm,is a complement to the existing conventional beam emission spectroscopy(BES)diagnostic.In this article,we introduce the progress of LyBES diagnostic,including the collection optics,the monochromator,and the detector system.The reflectance of the collection mirrors is measured to be~82%at 122 nm,and the aberration geometrical radius of the collection optics is tested to be~150μm in the aimed area.The linear dispersion of the LyBES monochromator is designed to be~0.09 nm mm^(-1).The bandwidth of the detector system with the 5×10^(7)V A^(-1)preamplifier gain is measured to be~280 kHz,and the peak-to-peak noise of the detector system is tested to be~16 mV.The finalized design,components development and testing of the LyBES diagnostic have been completed at present,and an overall performance of the LyBES diagnostic is to be confirmed in the next HL-2A campaign.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
In this article,the design of a Lyman-alpha-based beam emission spectroscopy(LAB)diagnostic on the HL-2A tokamak has been proposed for the first time.The purpose of this novel diagnostic is to measure density fluctuat...In this article,the design of a Lyman-alpha-based beam emission spectroscopy(LAB)diagnostic on the HL-2A tokamak has been proposed for the first time.The purpose of this novel diagnostic is to measure density fluctuations of tokamak plasma.The light-collection system of LAB,which consists of the first mirror and two groups of coaxial double-mirror telescopes,can realize a twosegmented viewing field ofρ=0–0.2 andρ=0.75–1,which is optimized to measure plasma density fluctuation,not only in the edge transport barrier region but also in the internal transport barrier region,to investigate the underlying physics of turbulence in tokamaks.Spectrometers are developed to separate out the Doppler-shifted target line(122.03 and 122.17 nm)from the background Lyman-alpha line(121.53 nm).Here,30 Core-LAB channels and 30 Edge-LAB channels are under development on the HL-2A tokamak.It has high radial spatial resolutions of about 2.7 mm and 3.3 mm for the core and edge channels,respectively.Taking the high light intensity of this Lyman-alpha line into account,temporal resolution of 200 k Hz can be ensured by broad bandwidth amplifiers.This high spatio-temporal resolution makes LAB a potential keen tool to experimentally investigate tokamak plasma physics.展开更多
“Green” has become a fundamental requirement for all development initiatives in China. The idea of harmonious coexistence between man and nature has gained significant prominence. General Secretary Xi Jinping places...“Green” has become a fundamental requirement for all development initiatives in China. The idea of harmonious coexistence between man and nature has gained significant prominence. General Secretary Xi Jinping places great importance on ecological and environmental protection, offering clear directives for ecological preservation efforts within the delivery industry [1]. He emphasizes the necessity to address packaging waste in online shopping and express delivery, eliminate excessive packaging, and reduce environmental waste and pollution. In this process, China Post will actively respond to the central government’s imperatives and formulate a series of strategies and plans, including green post ideas, transportation, packaging, and finance.展开更多
A newly developed Doppler coherence imaging spectroscopy(CIS)technique has been implemented in the HL-2 A tokamak for carbon impurity emissivity and flow measurement.In CIS diagnostics,the emissivity and flow profiles...A newly developed Doppler coherence imaging spectroscopy(CIS)technique has been implemented in the HL-2 A tokamak for carbon impurity emissivity and flow measurement.In CIS diagnostics,the emissivity and flow profiles inside the plasma are measured by a camera from the line-integrated emissivity and line-averaged flow,respectively.A standard inference method,called tomographic inversion,is necessary.Such an inversion is relatively challenging due to the ill-conditioned nature.In this article,we report the recent application and comparison of two different tomography algorithms,Gaussian process tomography and Tikhonov tomography,on light intensity measured by CIS,including feasibility and benchmark studies.Finally,the tomographic results for real measurement data in HL-2A are presented.展开更多
Objective:To evaluate the efficacy and safety of Yiqi Huoxue oral Chinese patent medicine in the treatment of angina pectoris.Methods:the databases of EMBASE,PubMed,CNKI,Wanfang and VIP were searched by computer,and t...Objective:To evaluate the efficacy and safety of Yiqi Huoxue oral Chinese patent medicine in the treatment of angina pectoris.Methods:the databases of EMBASE,PubMed,CNKI,Wanfang and VIP were searched by computer,and the randomized controlled trial(RCT)of Yiqi Huoxue Chinese patent medicine in the treatment of angina pectoris of coronary heart disease(CHD)was searched until December 2019.By using stata15.1 software,the total clinical effective rate,the improvement rate of ECG,the improvement rate of angina pectoris,the attack frequency and duration of angina pectoris were taken as the outcome indicators for network meta analysis and mapping.Results:51 RCTs were included,including 9 kinds of traditional Chinese medicine.The results of network meta analysis showed that:in terms of clinical total effective rate,the order was Shexiang Baoxin Pill(78.2%)>xueshuanxinming tablet>Dengzhan Shengmai capsule>Shengui Capsule>Tongxinluo capsule>Tongmai Yangxin pill>Yangxin tablet>Shexiang Tongxin drop pill>Naoxintong capsule;the improvement of ECG was Tongmai Yangxin pill(85.2%)>Yangxin tablet>Dengzhan Shengmai capsule>Shexiang Tongxin drop pill>Shexiang Baoxin Pill>Tongxinluo gum Capsule>Shengui Capsule>Naoxintong capsule;in order to reduce the frequency and duration of angina pectoris,they are conventional Naoxintong capsule(88.6%)>Shengui Capsule>Tongmai Yangxin pill>Shexiang Baoxin Pill>xueshuanxinmingpian>Tongxinluo capsule>Shexiang Tongxin drop pill>Dengzhan Shengmai capsule;Shexiang Baoxin Pill(66.9%)>Dengzhan Shengmai capsule>Shexiang Tongxin drop pill>Tongxinluo capsule>xueshuanxinmingning capsule Tablet>Tongmai Yangxin pill.Conclusion:Traditional Chinese medicine combined with western medicine has obvious advantages in the treatment of angina pectoris.Shexiang Baoxin Pill,Dengzhan Shengmai capsule and Tongmai Yangxin pill can be given priority.展开更多
A gas puff imaging(GPI) diagnostic has been developed and applied to measure edge plasma turbulence on the HL-2A tokamak.The principle and experimental setup of GPI are described.GPI is applied to investigate blobs in...A gas puff imaging(GPI) diagnostic has been developed and applied to measure edge plasma turbulence on the HL-2A tokamak.The principle and experimental setup of GPI are described.GPI is applied to investigate blobs in the edge and scrape-off layer.Statistical characterizations of GPI line emission intensity are calculated, including the probability density functions(PDFs),skewness, and kurtosis of the intensity, which are found to be consistent with measurements by Langmuir probes.Besides, the track of blob motions is recorded by time sequence of individual frames.The characteristics of the original images and the relatively high-frequency(>10 kHz)/low-frequency(1–10 kHz) component images are illustrated.The observation of the blob’s structures and high-speed motions proves the success and high performance of the GPI diagnostic.展开更多
A CO2 laser-based phase contrast imaging(PCI) diagnostic has been developed on HL-2A tokamak.It can detect line integrated plasma density fluctuations by measuring the phase shift of laser beam after being scattered b...A CO2 laser-based phase contrast imaging(PCI) diagnostic has been developed on HL-2A tokamak.It can detect line integrated plasma density fluctuations by measuring the phase shift of laser beam after being scattered by the bulk plasma.The diagnosed radial region ranges from ρ≡r/a =0.625 to 0.7.32-channel HgCdTe detectors with alternative-current biased amplifiers are arranged in line at the imaging plane of the optical path.This PCI is able to diagnose density fluctuations with wavenumbers ranging from 2 to 15 cm-1 and the time resolution is better than 2 μs.The first experimental data were achieved in 2018 spring campaign of HL-2A tokamak.High performance is confirmed in different discharging configurations and makes it a keen tool in broadband turbulence investigations.展开更多
The waves in a magnetic null could play important roles during 3D magnetic reconnection.Some preliminary clues in this paper show that the ion Bernstein wave(IBW)may be closely related to transport process in magnetic...The waves in a magnetic null could play important roles during 3D magnetic reconnection.Some preliminary clues in this paper show that the ion Bernstein wave(IBW)may be closely related to transport process in magnetic null region.The magnetic null configuration experiment reported here is set up in a linear helicon plasma device,Peking University plasma test device(PPT).The wave modes with frequencies between the first and third harmonics of local ion cyclotron frequency(w_(ci))are observed in the separatrix of magnetic null,which are identified as the IBW based on the dispersion relation.Further analysis shows that IBW could drive substantial particle flux across the magnetic separatrix.The theoretical radial particle flux driven by IBW and the measured parallel flow in PPT device are almost on the same order,which shows that IBW may play an important role during 3D reconnection process.展开更多
The influence of m/n=2/1(m and n are poloidal and toroidal mode numbers)tearing modes on plasma perpendicular flows and micro-fluctuations has been investigated in HL-2A neutral beam injection heated L-mode plasmas.It...The influence of m/n=2/1(m and n are poloidal and toroidal mode numbers)tearing modes on plasma perpendicular flows and micro-fluctuations has been investigated in HL-2A neutral beam injection heated L-mode plasmas.It is found that the local perpendicular rotation velocity and turbulence energy are modulated by the alternation between the island X-point and O-point of the naturally rotating tearing modes.Cross-correlation analysis indicates that the modulation of density fluctuations by the tearing mode is not only limited to the island region,but also occurs in the edge region near the last closed flux surface.The turbulence exhibits distinct spectral characteristics inside and outside the island region.In addition,it is observed that the particle flux near the strike point is also significantly impacted by the tearing modes.The experimental evidence reveals that there are strong core-edge interactions between the core tearing modes and the edge transport.展开更多
In this article,we present the optical design of a novel diagnostic on the HL-2A tokamak,i.e.the 20-channel edge Lyman-alpha beam emission spectroscopy,which is a promising solution for edge density turbulence researc...In this article,we present the optical design of a novel diagnostic on the HL-2A tokamak,i.e.the 20-channel edge Lyman-alpha beam emission spectroscopy,which is a promising solution for edge density turbulence research on tokamaks,as it offers the possibility of density fluctuation measurement with a 3.3 mm spatial resolution while maintains a high temporal resolution of 1μs.The optical path,including the reflective collection optics,the high-dispersion spectrometer,and the linear detector array,is carefully optimized to obtain a good image quality and a high throughput.The maximum root mean square radius of the collection optics is 64μm.The detected photon flux is estimated to be about 1011 photons/s/channel.展开更多
Effect of edge turbulent transport on scrape-off layer(SOL)width has been investigated in Ohmically heated L-mode plasma under limiter configurations on HL-2A tokamak.It has been found that SOL width is doubled when p...Effect of edge turbulent transport on scrape-off layer(SOL)width has been investigated in Ohmically heated L-mode plasma under limiter configurations on HL-2A tokamak.It has been found that SOL width is doubled when plasma current decreases about 20%.With larger plasma current,E×B shear is stronger and has greater suppression effect on edge turbulent transport.SOL width is larger when power of relative density fluctuation level in the edge region is larger.It is concluded that edge turbulent transport plays a significant role on SOL width.These experimental findings may provide a better understanding and controlling of power exhaust for present and future fusion devices.展开更多
The effect of resonant magnetic perturbation(RMP) on boundary turbulence and transport in J-TEXT plasma is experimentally investigated.Edge plasma fluctuations in discharges with and without the(m/n=3/1) RMP currents ...The effect of resonant magnetic perturbation(RMP) on boundary turbulence and transport in J-TEXT plasma is experimentally investigated.Edge plasma fluctuations in discharges with and without the(m/n=3/1) RMP currents are diagnosed by using Langmuir probe arrays.It was found that fluctuations in the edge and scrape-off layer(SOL) regions decrease with the application of a 6 kA RMP.The broadband turbulence at the radial location of ρ~0.9 which has a characteristic frequency of 40-150 kHz was strongly suppressed when applying RMP,as was the radial turbulent particle flux and blob transport in the near-SOL region.These experimental findings make RMP a promising method of suppressing and controlling turbulence and particle transport in a plasma boundary.展开更多
Sheath potential coefficient α is a key parameter, which is used to estimate plasma potential(Vp)for edge plasma physics study. Recently, a series of experiments has been carried out under hydrogen plasmas in the J-T...Sheath potential coefficient α is a key parameter, which is used to estimate plasma potential(Vp)for edge plasma physics study. Recently, a series of experiments has been carried out under hydrogen plasmas in the J-TEXT tokamak with swept probe, which is employed for current–voltage(I–V) characteristic measurement. Electron temperature is evaluated from I–V curve by three-parameter fitting method, and the electron energy probability function shows that electron distribution is Maxwellian both outside and inside of last closed flux surface(LCFS). Plasma potential is obtained by crossing point between I–V exponential fitting curve and electron saturation current extrapolating line, which is in good agreement with first derivative probe technique. The α coefficient profile in the vicinity of the LCFS is obtained, which is in the range of 2.1–3, and decreases from outside to inside of LCFS.展开更多
基金supported by Sichuan Science and Technology Program(No.2022JDJQ0038)the National Key R&D Program of China(Nos.2022YFE03100002 and 2018YFE0303102)National Natural Science Foundation of China(Nos.12205087 and 12075241)。
文摘An edge Lyman-alpha-based beam emission spectroscopy(LyBES)diagnostic,using a heating NBI(neutral beam injection)system,is currently under development on the HL-2A tokamak.The 20-channel edge LyBES,which is intended to measure the density fluctuation in plasma edge(from R=1960 mm to R=2026 mm)with an improved spatial resolution of 3.3 mm,is a complement to the existing conventional beam emission spectroscopy(BES)diagnostic.In this article,we introduce the progress of LyBES diagnostic,including the collection optics,the monochromator,and the detector system.The reflectance of the collection mirrors is measured to be~82%at 122 nm,and the aberration geometrical radius of the collection optics is tested to be~150μm in the aimed area.The linear dispersion of the LyBES monochromator is designed to be~0.09 nm mm^(-1).The bandwidth of the detector system with the 5×10^(7)V A^(-1)preamplifier gain is measured to be~280 kHz,and the peak-to-peak noise of the detector system is tested to be~16 mV.The finalized design,components development and testing of the LyBES diagnostic have been completed at present,and an overall performance of the LyBES diagnostic is to be confirmed in the next HL-2A campaign.
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 R&D Program of China(Nos.2022YFE03100002,2017YFE0301201 and 2018YFE0303102)Sichuan Science and Technology Program(Nos.2022JDJQ0038 and 2020JDTD0030)National Natural Science Foundation of China(No.12205087)。
文摘In this article,the design of a Lyman-alpha-based beam emission spectroscopy(LAB)diagnostic on the HL-2A tokamak has been proposed for the first time.The purpose of this novel diagnostic is to measure density fluctuations of tokamak plasma.The light-collection system of LAB,which consists of the first mirror and two groups of coaxial double-mirror telescopes,can realize a twosegmented viewing field ofρ=0–0.2 andρ=0.75–1,which is optimized to measure plasma density fluctuation,not only in the edge transport barrier region but also in the internal transport barrier region,to investigate the underlying physics of turbulence in tokamaks.Spectrometers are developed to separate out the Doppler-shifted target line(122.03 and 122.17 nm)from the background Lyman-alpha line(121.53 nm).Here,30 Core-LAB channels and 30 Edge-LAB channels are under development on the HL-2A tokamak.It has high radial spatial resolutions of about 2.7 mm and 3.3 mm for the core and edge channels,respectively.Taking the high light intensity of this Lyman-alpha line into account,temporal resolution of 200 k Hz can be ensured by broad bandwidth amplifiers.This high spatio-temporal resolution makes LAB a potential keen tool to experimentally investigate tokamak plasma physics.
文摘“Green” has become a fundamental requirement for all development initiatives in China. The idea of harmonious coexistence between man and nature has gained significant prominence. General Secretary Xi Jinping places great importance on ecological and environmental protection, offering clear directives for ecological preservation efforts within the delivery industry [1]. He emphasizes the necessity to address packaging waste in online shopping and express delivery, eliminate excessive packaging, and reduce environmental waste and pollution. In this process, China Post will actively respond to the central government’s imperatives and formulate a series of strategies and plans, including green post ideas, transportation, packaging, and finance.
文摘A newly developed Doppler coherence imaging spectroscopy(CIS)technique has been implemented in the HL-2 A tokamak for carbon impurity emissivity and flow measurement.In CIS diagnostics,the emissivity and flow profiles inside the plasma are measured by a camera from the line-integrated emissivity and line-averaged flow,respectively.A standard inference method,called tomographic inversion,is necessary.Such an inversion is relatively challenging due to the ill-conditioned nature.In this article,we report the recent application and comparison of two different tomography algorithms,Gaussian process tomography and Tikhonov tomography,on light intensity measured by CIS,including feasibility and benchmark studies.Finally,the tomographic results for real measurement data in HL-2A are presented.
基金Applied technology research and development plan of Heilongjiang province(No.GY2019YF0237)National training program for innovative young talents if traditional Chinese medicine(No.14061190007)。
文摘Objective:To evaluate the efficacy and safety of Yiqi Huoxue oral Chinese patent medicine in the treatment of angina pectoris.Methods:the databases of EMBASE,PubMed,CNKI,Wanfang and VIP were searched by computer,and the randomized controlled trial(RCT)of Yiqi Huoxue Chinese patent medicine in the treatment of angina pectoris of coronary heart disease(CHD)was searched until December 2019.By using stata15.1 software,the total clinical effective rate,the improvement rate of ECG,the improvement rate of angina pectoris,the attack frequency and duration of angina pectoris were taken as the outcome indicators for network meta analysis and mapping.Results:51 RCTs were included,including 9 kinds of traditional Chinese medicine.The results of network meta analysis showed that:in terms of clinical total effective rate,the order was Shexiang Baoxin Pill(78.2%)>xueshuanxinming tablet>Dengzhan Shengmai capsule>Shengui Capsule>Tongxinluo capsule>Tongmai Yangxin pill>Yangxin tablet>Shexiang Tongxin drop pill>Naoxintong capsule;the improvement of ECG was Tongmai Yangxin pill(85.2%)>Yangxin tablet>Dengzhan Shengmai capsule>Shexiang Tongxin drop pill>Shexiang Baoxin Pill>Tongxinluo gum Capsule>Shengui Capsule>Naoxintong capsule;in order to reduce the frequency and duration of angina pectoris,they are conventional Naoxintong capsule(88.6%)>Shengui Capsule>Tongmai Yangxin pill>Shexiang Baoxin Pill>xueshuanxinmingpian>Tongxinluo capsule>Shexiang Tongxin drop pill>Dengzhan Shengmai capsule;Shexiang Baoxin Pill(66.9%)>Dengzhan Shengmai capsule>Shexiang Tongxin drop pill>Tongxinluo capsule>xueshuanxinmingning capsule Tablet>Tongmai Yangxin pill.Conclusion:Traditional Chinese medicine combined with western medicine has obvious advantages in the treatment of angina pectoris.Shexiang Baoxin Pill,Dengzhan Shengmai capsule and Tongmai Yangxin pill can be given priority.
基金supported by the National Key Research and Development Program of China (No.2017YFE0300405)National Natural Science Foundation of China (Nos.11575055, 11705052, 11875124, 11475058, and 11475056)+1 种基金the National Key Research and Development Program of China (Nos.2017YFE0301201, 2018YFE0303102, 2018YFE0309103)the Chinese National Fusion Project for ITER (No.2015GB104000)
文摘A gas puff imaging(GPI) diagnostic has been developed and applied to measure edge plasma turbulence on the HL-2A tokamak.The principle and experimental setup of GPI are described.GPI is applied to investigate blobs in the edge and scrape-off layer.Statistical characterizations of GPI line emission intensity are calculated, including the probability density functions(PDFs),skewness, and kurtosis of the intensity, which are found to be consistent with measurements by Langmuir probes.Besides, the track of blob motions is recorded by time sequence of individual frames.The characteristics of the original images and the relatively high-frequency(>10 kHz)/low-frequency(1–10 kHz) component images are illustrated.The observation of the blob’s structures and high-speed motions proves the success and high performance of the GPI diagnostic.
基金supported by the National Key Research and Development Program of China (No.2017YFE0300405)National Natural Science Foundation of China (Nos.11875124, 11705052, 11575055 and 11611130164)the National Magnetic Confinement Fusion Science Program of China (No.2015GB120002)
文摘A CO2 laser-based phase contrast imaging(PCI) diagnostic has been developed on HL-2A tokamak.It can detect line integrated plasma density fluctuations by measuring the phase shift of laser beam after being scattered by the bulk plasma.The diagnosed radial region ranges from ρ≡r/a =0.625 to 0.7.32-channel HgCdTe detectors with alternative-current biased amplifiers are arranged in line at the imaging plane of the optical path.This PCI is able to diagnose density fluctuations with wavenumbers ranging from 2 to 15 cm-1 and the time resolution is better than 2 μs.The first experimental data were achieved in 2018 spring campaign of HL-2A tokamak.High performance is confirmed in different discharging configurations and makes it a keen tool in broadband turbulence investigations.
基金supported by National Natural Science Foundation of China(No.11975038)the National MCF Energy R&D Program of China(Nos.2017YFE0300601 and 2018YFE0311400).
文摘The waves in a magnetic null could play important roles during 3D magnetic reconnection.Some preliminary clues in this paper show that the ion Bernstein wave(IBW)may be closely related to transport process in magnetic null region.The magnetic null configuration experiment reported here is set up in a linear helicon plasma device,Peking University plasma test device(PPT).The wave modes with frequencies between the first and third harmonics of local ion cyclotron frequency(w_(ci))are observed in the separatrix of magnetic null,which are identified as the IBW based on the dispersion relation.Further analysis shows that IBW could drive substantial particle flux across the magnetic separatrix.The theoretical radial particle flux driven by IBW and the measured parallel flow in PPT device are almost on the same order,which shows that IBW may play an important role during 3D reconnection process.
基金the National Key R&D Program of China(Nos.2017YFE0301201 and 2017YFE0301106)National Natural Science Foundation of China(Nos.11705051,11820101004,11875021 and 11775069)the Young Elite Scientists Sponsorship Program by CAST(No.2018QNRC001).
文摘The influence of m/n=2/1(m and n are poloidal and toroidal mode numbers)tearing modes on plasma perpendicular flows and micro-fluctuations has been investigated in HL-2A neutral beam injection heated L-mode plasmas.It is found that the local perpendicular rotation velocity and turbulence energy are modulated by the alternation between the island X-point and O-point of the naturally rotating tearing modes.Cross-correlation analysis indicates that the modulation of density fluctuations by the tearing mode is not only limited to the island region,but also occurs in the edge region near the last closed flux surface.The turbulence exhibits distinct spectral characteristics inside and outside the island region.In addition,it is observed that the particle flux near the strike point is also significantly impacted by the tearing modes.The experimental evidence reveals that there are strong core-edge interactions between the core tearing modes and the edge transport.
基金supported by the National Key R&D Program of China(Nos.2017YFE0301201 and 2018YFE0303102)National Natural Science Foundation of China(Nos.11875124 and 12075241).
文摘In this article,we present the optical design of a novel diagnostic on the HL-2A tokamak,i.e.the 20-channel edge Lyman-alpha beam emission spectroscopy,which is a promising solution for edge density turbulence research on tokamaks,as it offers the possibility of density fluctuation measurement with a 3.3 mm spatial resolution while maintains a high temporal resolution of 1μs.The optical path,including the reflective collection optics,the high-dispersion spectrometer,and the linear detector array,is carefully optimized to obtain a good image quality and a high throughput.The maximum root mean square radius of the collection optics is 64μm.The detected photon flux is estimated to be about 1011 photons/s/channel.
基金by National Natural Science Foundation of China(Nos.11875124,U1867222,11575055,11705052,11875020 and 11705151)National Key Research and Development Program of China(Nos.2018YFE0309103,2018YFE0303102,2017YFE0300405 and 2017YFE0301203).
文摘Effect of edge turbulent transport on scrape-off layer(SOL)width has been investigated in Ohmically heated L-mode plasma under limiter configurations on HL-2A tokamak.It has been found that SOL width is doubled when plasma current decreases about 20%.With larger plasma current,E×B shear is stronger and has greater suppression effect on edge turbulent transport.SOL width is larger when power of relative density fluctuation level in the edge region is larger.It is concluded that edge turbulent transport plays a significant role on SOL width.These experimental findings may provide a better understanding and controlling of power exhaust for present and future fusion devices.
基金supported by the National Key Research & Development Programme of China (No. 2018YFE0309100, 2017YFE0301201)National Natural Science Foundation of China (Nos. 11875124, U1867222, 11575055, 11705052 & 11705151)the National Magnetic Confinement Fusion Science Programme of China (Nos. 2015GB120002, 2015GB11101 & 2015GB104000)
文摘The effect of resonant magnetic perturbation(RMP) on boundary turbulence and transport in J-TEXT plasma is experimentally investigated.Edge plasma fluctuations in discharges with and without the(m/n=3/1) RMP currents are diagnosed by using Langmuir probe arrays.It was found that fluctuations in the edge and scrape-off layer(SOL) regions decrease with the application of a 6 kA RMP.The broadband turbulence at the radial location of ρ~0.9 which has a characteristic frequency of 40-150 kHz was strongly suppressed when applying RMP,as was the radial turbulent particle flux and blob transport in the near-SOL region.These experimental findings make RMP a promising method of suppressing and controlling turbulence and particle transport in a plasma boundary.
基金supported by the National Key Research and Development Program of China (No. 2018YFE0309103)National Natural Science Foundation of China (Nos. 11875020, 11705052, 11875124 and U1867222)the ITER Organization and China Domestic Agency for the support of this work (ITER5.5.P01.CN.05)。
文摘Sheath potential coefficient α is a key parameter, which is used to estimate plasma potential(Vp)for edge plasma physics study. Recently, a series of experiments has been carried out under hydrogen plasmas in the J-TEXT tokamak with swept probe, which is employed for current–voltage(I–V) characteristic measurement. Electron temperature is evaluated from I–V curve by three-parameter fitting method, and the electron energy probability function shows that electron distribution is Maxwellian both outside and inside of last closed flux surface(LCFS). Plasma potential is obtained by crossing point between I–V exponential fitting curve and electron saturation current extrapolating line, which is in good agreement with first derivative probe technique. The α coefficient profile in the vicinity of the LCFS is obtained, which is in the range of 2.1–3, and decreases from outside to inside of LCFS.
