The progress of a microbeam facility in the Institute of Plasma Physics was discussed in this paper. This kind of equipment can supply single-particle beam which may be implanted into cells in micrometer-radius and me...The progress of a microbeam facility in the Institute of Plasma Physics was discussed in this paper. This kind of equipment can supply single-particle beam which may be implanted into cells in micrometer-radius and measured by a new outstanding detector among global microbeam systems. Measurements by some plain targets showed that the highest current after the accelerator tube can be larger than 20 /μA, the H_2^+ current before the second bending magnet is near 0.9 /μA, the current after the second bending magnet is near 0.8 μA, and the current of the beam line (after a 2-mm diameter aperture) is near 0.25 nA which is enough for the single-particle microbeam experiment. It took scientists 3 months to do their microbeam experiment after setting up the accelerator beam line and get the microbeam from this equipment. Two pre-collimators were installed between the 2-mm diameter aperture and the collimator to survey the beam. Tracks on the CR39 film etched in the solution of NaOH showed that the beam can go through the collimator including a 10 μm diameter aperture and the 3.5 μm thick vacuum sealing film (Mylar). A new method, which is called optimization of the beam quality, was put forward in this paper, in order to get smaller diameter of beam-spot in microbeam system.展开更多
The Experiments, methods and results of obtaining micron beam in the Microbeam Facility of the Institute of Plasma Physics were discussed in this paper. The H+2 beam was accelerated by the Van de GraafF electrostatic ...The Experiments, methods and results of obtaining micron beam in the Microbeam Facility of the Institute of Plasma Physics were discussed in this paper. The H+2 beam was accelerated by the Van de GraafF electrostatic accelerator, and the collimator at the end of the beam line is a 60 μm thick stainless steel chip. And as a result, particle tracks on the solid track probes (CR39 film) etched in the solution of NaOH showed that the beam can go through the collimator with a small aperure (2000, 300, 55, 30, or 10 μm) and 3.5 μm thick vacuum film (Mylar). Besides the CR39 method, the beam was measured by an energy spectrum detector after the 10 μm diameter aperture and the 3.5 μm thick vacuum film too.展开更多
At the EAST tokamak, the ion temperature(T_(i)) is observed to be clamped around 1.25 keV in electron cyclotron resonance(ECR)-heated plasmas, even at core electron temperatures up to 10 keV(depending on the ECR heati...At the EAST tokamak, the ion temperature(T_(i)) is observed to be clamped around 1.25 keV in electron cyclotron resonance(ECR)-heated plasmas, even at core electron temperatures up to 10 keV(depending on the ECR heating power and the plasma density). This clamping results from the lack of direct ion heating and high levels of turbulence-driven transport. Turbulent transport analysis shows that trapped electron mode and electron temperature gradient-driven modes are the most unstable modes in the core of ECR-heated H-mode plasmas. Nevertheless, recently it was found that the T_(i)/T_(e)ratio can increase further with the fraction of the neutral beam injection(NBI) power, which leads to a higher core ion temperature(Ti0). In NBI heating-dominant H-mode plasmas, the ion temperature gradient-driven modes become the most unstable modes.Furthermore, a strong and broad internal transport barrier(ITB) can form at the plasma core in high-power NBI-heated H-mode plasmas when the T_(i)/T_(e)ratio approaches ~1, which results in steep core Teand Tiprofiles, as well as a peaked neprofile. Power balance analysis shows a weaker Teprofile stiffness after the formation of ITBs in the core plasma region, where Ticlamping is broken,and the core Tican increase further above 2 keV, which is 80% higher than the value of Ticlamping in ECR-heated plasmas. This finding proposes a possible solution to the problem of Ticlamping on EAST and demonstrates an advanced operational regime with the formation of a strong and broad ITB for future fusion plasmas dominated by electron heating.展开更多
This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SLM).The powder material was conso...This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SLM).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the SLM material and unmeasurably low porosity in the SPS material.The main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion resistance.Both materials showed comparable strength of∼110 MPa in tension and compression and relatively good deformability of∼9%and∼21%for the SLM and SPS materials,respectively.The corrosion resistance of the SPS material in 0.1 M NaCl solution was superior to the SLM one and comparable to the conventional extruded material.The digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the SLM material.On the other hand,one of the primary outcomes of this study is that the SPS consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.展开更多
Quasi-coherent micro-instabilities is one of the key topics of magnetic confinement fusion. This work focuses on the quasi-coherent spectra of ion temperature gradient(ITG) and trapped-electron-mode instabilities usin...Quasi-coherent micro-instabilities is one of the key topics of magnetic confinement fusion. This work focuses on the quasi-coherent spectra of ion temperature gradient(ITG) and trapped-electron-mode instabilities using newly developed far-forward collective scattering measurements within ohmic plasmas in the J-TEXT tokamak.The ITG mode is characterized by frequencies ranging from 30 to 100 k Hz and wavenumbers(k_(θρs)) less than 0.3. Beyond a critical plasma density threshold, the ITG mode undergoes a bifurcation, which is marked by a reduction in frequency and an enhancement in amplitude. Concurrently, enhancements in ion energy loss and degradation in confinement are observed. This ground-breaking discovery represents the first instance of direct experimental evidence that establishes a clear link between ITG instability and ion thermal transport.展开更多
Multifaceted asymmetric radiation from the edge(MARFE) movement which can cause density limit disruption is often encountered during high density operation on many tokamaks. Therefore, identifying and predicting MARFE...Multifaceted asymmetric radiation from the edge(MARFE) movement which can cause density limit disruption is often encountered during high density operation on many tokamaks. Therefore, identifying and predicting MARFE movement is meaningful to mitigate or avoid density limit disruption for the steady-state high-density plasma operation. A machine learning method named random forest(RF) has been used to predict the MARFE movement based on the density ramp-up experiment in the 2022’s first campaign of Experimental Advanced Superconducting Tokamak(EAST). The RF model shows that besides Greenwald fraction which is the ratio of plasma density and Greenwald density limit, dβp/dt,H98and d Wmhd/dt are relatively important parameters for MARFE-movement prediction. Applying the RF model on test discharges, the test results show that the successful alarm rate for MARFE movement causing density limit disruption reaches ~ 85% with a minimum alarm time of ~ 40 ms and mean alarm time of ~ 700 ms. At the same time, the false alarm rate for non-disruptive and non-density-limit disruptive discharges can be kept below 5%. These results provide a reference to the prediction of MARFE movement in high density plasmas, which can help the avoidance or mitigation of density limit disruption in future fusion reactors.展开更多
The linear behavior of the dominant unstable mode(m=2,n=1)and its high order harmonics(m=2n,n≥2)are numerically investigated in a reversed magnetic shear cylindrical plasma with two q=2 rational surfaces on the basis...The linear behavior of the dominant unstable mode(m=2,n=1)and its high order harmonics(m=2n,n≥2)are numerically investigated in a reversed magnetic shear cylindrical plasma with two q=2 rational surfaces on the basis of the non-reduced magnetohydrodynamics(MHD)equations.The results show that with low beta(beta is defined as the ratio of plasma pressure to magnetic field pressure),the dominant mode is a classical double tearing mode(DTM).However,when the beta is sufficiently large,the mode is driven mainly by plasma pressure.In such a case,both the linear growth rate and mode structures are strongly affected by pressure,while almost independent of the resistivity.This means that the dominant mode undergoes a transition from DTM to pressure-driven mode with the increase of pressure,which is consistent with the experimental result in ASDEX Upgrade.The simulations also show that the distance between two rational surfaces has an important influence on the pressure needed in mode transition.The larger the distance between two rational surfaces,the larger the pressure for driving the mode transition is.Motivated by the phenomena that the high-m modes may dominate over low-m modes at small inter-resonance distance,the high-m modes with different pressures and q profiles are studied too.展开更多
The investigation of electron cyclotron(EC)wave absorption and current drive has been performed for the China Fusion Engineering Test Reactor(CFETR)hybrid scenarios using the TORAY code.To achieve the physics goal of ...The investigation of electron cyclotron(EC)wave absorption and current drive has been performed for the China Fusion Engineering Test Reactor(CFETR)hybrid scenarios using the TORAY code.To achieve the physics goal of the EC system in CFETR,a total of four wave frequency values and nine locations of launching antennas have been considered,and the injection poloidal and toroidal angles have been scanned systematically.The electron cyclotron current drive(ECCD)efficiency of the 170 GHz EC system is quite low due to the wave-particle interactions being located at the low-field side.To optimize the ECCD efficiency,the wave frequency is increased up to 221–250 GHz,which leads to the power being deposited at the high-field side.The off-axis ECCD efficiency can be significantly enhanced by launching EC waves from the top window and injecting them towards the high-field side.The optimized ECCD efficiency atρ=0.32 and atρ=0.4 is 2.9 and 2.2 times that of 170 GHz,respectively.展开更多
High-order harmonics q(ψ_(s))=1 energetic particle modes(EPMs)have been observed in toroidal plasmas experiments with neutral beam injection.To investigate these phenomena,linear properties and nonlinear dynamics of ...High-order harmonics q(ψ_(s))=1 energetic particle modes(EPMs)have been observed in toroidal plasmas experiments with neutral beam injection.To investigate these phenomena,linear properties and nonlinear dynamics of these EPMs driven by passing energetic particles(EPs)are studied via the global hybrid kinetic-magnetohydrodynamic code M3D-K.Simulation results demonstrate that passing EPs'effects on high mode-number harmonics(q(ψ_(s))=m/n=2/2,3/3,4/4)instability are more obvious than the q(ψ_(s))=1/1 mode,especially when q-profile is sufficiently flat in the core region.Furthermore,the effects of the pitch angleΛ_0 and beam ion pressure P_(hot)/P_(total)on the features of high n components are also analyzed specifically.It is found that there exists only one resonant condition for these EPMs.In the nonlinear phase,these high mode-number harmonics can induce significant energetic ions redistribution and chirping up phenomena,which differs from the classical fishbone excited by passing EPs.These discoveries are conducive to better apprehend the underlying physical mechanisms of the highorder harmonics driven by passing EPs.展开更多
Massive gas injection(MGI)is a traditional plasma disruption mitigation method.This method directly injected massive gas into the pre-disruption plasma and had been developed on the Experimental Advanced Superconducti...Massive gas injection(MGI)is a traditional plasma disruption mitigation method.This method directly injected massive gas into the pre-disruption plasma and had been developed on the Experimental Advanced Superconducting Tokamak(EAST).Different noble gas injection experiments,including He,Ne,and Ar,were performed to compare the mitigation effect of plasma disruption by evaluating the key parameters such as flight time,pre-thermal quench(pre-TQ),and current quench(CQ).The flight time was shorter for low atomic number(Z)gas,and the decrease in flight time by increasing the amount of gas was insignificant.However,both pre-TQ and CQ durations decreased considerably with the increase in gas injection amount.The effect of atomic mass on pre-TQ and CQ durations showed the opposite trend.The observed trend could help in controlling CQ duration in a reasonable area.Moreover,the analysis of radiation distribution with different impurity injections indicated that low Z impurity could reduce the asymmetry of radiation,which is valuable in mitigating plasma disruption.These results provided essential data support for plasma disruption mitigation on EAST and future fusion devices.展开更多
A quasi-coherent(QC)mode was observed in the core region of low-density ohmic plasmas in Sino-UNIted Spherical Tokamak.In experiments on the QC mode,two sets of moveable Langmuir probes(LPs)were used to measure the lo...A quasi-coherent(QC)mode was observed in the core region of low-density ohmic plasmas in Sino-UNIted Spherical Tokamak.In experiments on the QC mode,two sets of moveable Langmuir probes(LPs)were used to measure the local parameters including floating potential,electron temperature,electron density,and so on,as well as their profiles.To monitor the magnetohydrodynamic activities,a Mirnov probe was used to measure the poloidal magnetic fluctuation.The QC mode can be seen in the spectra of floating potential,but there is no similar peak in the spectra of magnetic fluctuation.Thus,the QC mode is probably electrostatic.By analyzing the electrostatic potential fluctuations from the LPs,the features of the QC mode including frequency,wavenumber,propagation direction,and dependence on collisionality are identified,which are consistent with the characteristics of dissipative trapped electron mode.展开更多
To better understand divertor detachment and asymmetry in the Experimental Advanced Superconducting Tokamak(EAST),drift modeling via the comprehensive edge plasma code SOLPS-ITER of neon impurity seeded plasmas in fav...To better understand divertor detachment and asymmetry in the Experimental Advanced Superconducting Tokamak(EAST),drift modeling via the comprehensive edge plasma code SOLPS-ITER of neon impurity seeded plasmas in favorable/unfavorable toroidal magnetic field(BT)has been performed.Firstly,electrostatic potential/field(f/E)distribution has been analyzed,to make sure that f and E are correctly described and to better understand drift-driven processes.After that,drift effects on divertor detachment and asymmetry have been focused on.In accordance with the corresponding experimental observations,simulation results demonstrate that in favorable BTthe onset of detachment is highly asymmetric between the inner and outer divertors;and reversing BT can significantly decrease the magnitude of in-out asymmetry in the onset of detachment,physics reasons for which have been explored.It is found that,apart from the well-known E×B drift particle flow from one divertor to the other through the private flux region,scrape-off layer(SOL)heat flow,which is much more asymmetrically distributed between the high field side and low field side for favorable BTthan that for unfavorable B_T,is also a critical parameter affecting divertor detachment and asymmetry.During detachment,upstream pressure(P_u)reduction occurs and tends to be more dramatical in the colder side than that in the hotter side.The convective SOL heat flow,emerging due to in-out asymmetry in P_u reduction,is found to be critical for understanding divertor detachment and asymmetry observed in EAST.To better understand the calculated drastic power radiation in the core and upstream SOL,drift effects on divertor leakage/retention of neon in EAST with both BTdirections have been addressed for the first time,by analyzing profile of poloidal neon velocity and that of neon ionization source from atoms.This work can be a reference for future numeric simulations performed more closely related to experimental regimes.展开更多
A discharge with electron temperature up to 14 keV has been achieved in EAST.Analysis of the electron cyclotron current drive(ECCD)efficiency at high electron temperature under EAST parameters is presented using C3PO/...A discharge with electron temperature up to 14 keV has been achieved in EAST.Analysis of the electron cyclotron current drive(ECCD)efficiency at high electron temperature under EAST parameters is presented using C3PO/LUKE code.Simulation results show that the ECCD efficiency of X-mode increases with central electron temperature up to 10 keV and then starts to decrease above 10 keV,at a specific magnetic field and toroidal angle.The efficiency degradation is due to the presence of the third harmonic extraordinary(X3)downshifted absorption at the low field side(LFS);even the cold resonance of X3 mode is located outside the plasma.As the electron temperature increases from 5 to 20 ke V,the X3 absorption increases from 0.9%to 96.4%.The trapping electron effect at the LFS produces a reverse Ohkawa current.The competition between the Fisch–Boozer current drive and the Ohkawa current drive results in a decrease in ECCD efficiency.ECCD efficiency optimization is achieved through two methods.One is to increase the toroidal angle,leading to X2 mode predominating again over X3 mode and the electron resonance domain of X2 mode moving far from the trapped/passing boundary.The second one is to increase the magnetic field to move away the X3 resonance layer from the plasma,hence less EC power absorbed by X3 mode.展开更多
Sulfamethoxazole(SMX)is an antibiotic and widely present in aquatic environments,so it presents a serious threat to human health and sustainable development.A dielectric barrier discharge(DBD)plasma jet was utilized t...Sulfamethoxazole(SMX)is an antibiotic and widely present in aquatic environments,so it presents a serious threat to human health and sustainable development.A dielectric barrier discharge(DBD)plasma jet was utilized to degrade aqueous SMX,and the effects of various operating parameters(working gas,discharge power,etc)on SMX degradation performance were studied.The experimental results showed that the DBD plasma jet can obtain a relatively high degradation efficiency for SMX when the discharge power is high with an oxygen atmosphere,the initial concentration of SMX is low,and the aqueous solution is under acidic conditions.The reactive species produced in the liquid phase were detected,and OH radicals and O3were found to play a significant role in the degradation of SMX.Moreover,the process of SMX degradation could be better fitted by the quasi-first-order reaction kinetic equation.The analysis of the SMX degradation process indicated that SMX was gradually decomposed and 4-amino benzene sulfonic acid,benzene sulfonamide,4-nitro SMX,and phenylsulfinyl acid were detected,and thus three possible degradation pathways were finally proposed.The mineralization degree of SMX reached 90.04%after plasma treatment for 20 min,and the toxicity of the solution fluctuated with the discharge time but eventually decreased.展开更多
The erosion loss of cathode is essential for the lifetime of magnetoplasmadynamic thruster(MPDT).In this work,an endurance test system for MPDT cathodes was designed and developed,and the erosion characteristics,erosi...The erosion loss of cathode is essential for the lifetime of magnetoplasmadynamic thruster(MPDT).In this work,an endurance test system for MPDT cathodes was designed and developed,and the erosion characteristics,erosion rate and erosion mechanism of the cathode were studied using the system under vacuum condition.The WCe20 hollow cathode was selected to carry out the long-term erosion of 540 h with the argon propellant supply flow rate of40 ml min^(-1),the input current of 25 A,and the central magnetic field intensity of 96 Gs.In order to predict the theoretical service life of cathode,a steady state erosion numerical model was established.The calculation results show that the total erosion rate of sputtering and evaporation is 11.58 mg h^(-1),which is slightly smaller than the test data of the average cathode corrosion rate of 12.70 mg h^(-1) in the experiment,because the experimental value includes start-up erosion rate.展开更多
In an experiment carried out at the Prague Asterix Laser System at laser intensities relevant to shock ignition conditions(I>10^(16) W/cm^(2)),the heating and transport of hot electrons were studied by using severa...In an experiment carried out at the Prague Asterix Laser System at laser intensities relevant to shock ignition conditions(I>10^(16) W/cm^(2)),the heating and transport of hot electrons were studied by using several complementary diagnostics,i.e.,K_(α)time-resolved imaging,hard x-ray filtering(a bremsstrahlung cannon),and electron spectroscopy.Ablators with differing composition from low Z(parylene N)to high Z(nickel)were used in multilayer planar targets to produce plasmas with different coronal temperature and collisionality and modify the conditions of hot-electron generation.The variety of available diagnostics allowed full characterization of the population of hot electrons,retrieving their conversion efficiency,time generation and duration,temperature,and angular divergence.The obtained results are shown to be consistent with those from detailed simulations and similar inertial confinement fusion experiments.Based on the measured data,the advantages,reliability,and complementarity of the experimental diagnostics are discussed.展开更多
The rapid development of high-intensity laser-generated particle and photon secondary sources has attracted widespread interest during the last 20 years not only due to fundamental science research but also because of...The rapid development of high-intensity laser-generated particle and photon secondary sources has attracted widespread interest during the last 20 years not only due to fundamental science research but also because of the important applications of this developing technology.For instance,the generation of relativistic particle beams,betatron-type coherent X-ray radiation and high harmonic generation have attracted interest from various fields of science and technology owing to their diverse applications in biomedical,material science,energy,space,and security applications.In the field of biomedical applications in particular,laser-driven particle beams as well as laser-driven X-ray sources are a promising field of study.This article looks at the research being performed at the Institute of Plasma Physics and Lasers(IPPL)of the Hellenic Mediterranean University Research Centre.The recent installation of the ZEUS 45 TW laser system developed at IPPL offers unique opportunities for research in laser-driven particle and X-ray sources.This article provides information about the facility and describes initial experiments performed for establishing the baseline platforms for secondary plasma sources.展开更多
A gas puff imaging(GPI)diagnostic has been developed and operated on EAST since 2012,and the time-delay estimation(TDE)method is used to derive the propagation velocity of fluctuations from the two-dimensional GPI dat...A gas puff imaging(GPI)diagnostic has been developed and operated on EAST since 2012,and the time-delay estimation(TDE)method is used to derive the propagation velocity of fluctuations from the two-dimensional GPI data.However,with the TDE method it is difficult to analyze the data with fast transient events,such as edge-localized mode(ELM).Consequently,a method called the spatial displacement estimation(SDE)algorithm is developed to estimate the turbulence velocity with high temporal resolution.Based on the SDE algorithm,we make some improvements,including an adaptive median filter and super-resolution technology.After the development of the algorithm,a straight-line movement and a curved-line movement are used to test the accuracy of the algorithm,and the calculated speed agrees well with preset speed.This SDE algorithm is applied to the EAST GPI data analysis,and the derived propagation velocity of turbulence is consistent with that from the TDE method,but with much higher temporal resolution.展开更多
Measurement of plasma electron density by far-infrared laser polarimetry has become a routine and indispensable tool in magnetic confinement fusion research.This article presents the design of a Cotton-Mouton polarime...Measurement of plasma electron density by far-infrared laser polarimetry has become a routine and indispensable tool in magnetic confinement fusion research.This article presents the design of a Cotton-Mouton polarimeter interferometer,which provides a reliable density measurement without fringe jumps.Cotton-Mouton effect on Experimental Advanced Superconducting Tokamak(EAST)is studied by Stokes equation with three parameters(s_(1),s_(2),s_(3)).It demonstrates that under the condition of a small Cotton-Mouton effect,parameter s_(2)contains information about Cotton-Mouton effect which is proportional to the line-integrated density.For a typical EAST plasma,the magnitude of Cotton-Mouton effects is less than 2πfor laser wavelength of 432μm.Refractive effect due to density gradient is calculated to be negligible.Time modulation of Stokes parameters(s_(2),s_(3))provides heterodyne measurement.Due to the instabilities arising from laser oscillation and beam refraction in plasmas,it is necessary for the system to be insensitive to variations in the amplitude of the detection signal.Furthermore,it is shown that non-equal amplitude of X-mode and O-mode within a certain range only affects the DC offset of Stokes parameters(s_(2),s_(3))but does not greatly influence the phase measurements of Cotton-Mouton effects.展开更多
Plasma equilibrium reconstruction provides essential information for tokamak operation and physical analysis.An extensive and reliable set of magnetic diagnostics is required to obtain accurate plasma equilibrium.This...Plasma equilibrium reconstruction provides essential information for tokamak operation and physical analysis.An extensive and reliable set of magnetic diagnostics is required to obtain accurate plasma equilibrium.This study designs and optimizes the magnetic diagnostics layout for the reconstruction of the equilibrium of the plasma according to the scientific objectives,engineering design parameters,and limitations of the Chinese Fusion Engineering Test Reactor(CFETR).Based on the CFETR discharge simulation,magnetic measurement data are employed to reconstruct consistent plasma equilibrium parameters,and magnetic diagnostics'number and position are optimized by truncated Singular value decomposition,verifying the redundancy reliability of the magnetic diagnostics layout design.This provides a design solution for the layout of the magnetic diagnostics system required to control the plasma equilibrium of CFETR,and the developed design and optimization method can provide effective support to design magnetic diagnostics systems for future magnetic confinement fusion devices.展开更多
基金The project supported by the Natural Science Foundation Committee in Anhui Province, China (No. 01046201)
文摘The progress of a microbeam facility in the Institute of Plasma Physics was discussed in this paper. This kind of equipment can supply single-particle beam which may be implanted into cells in micrometer-radius and measured by a new outstanding detector among global microbeam systems. Measurements by some plain targets showed that the highest current after the accelerator tube can be larger than 20 /μA, the H_2^+ current before the second bending magnet is near 0.9 /μA, the current after the second bending magnet is near 0.8 μA, and the current of the beam line (after a 2-mm diameter aperture) is near 0.25 nA which is enough for the single-particle microbeam experiment. It took scientists 3 months to do their microbeam experiment after setting up the accelerator beam line and get the microbeam from this equipment. Two pre-collimators were installed between the 2-mm diameter aperture and the collimator to survey the beam. Tracks on the CR39 film etched in the solution of NaOH showed that the beam can go through the collimator including a 10 μm diameter aperture and the 3.5 μm thick vacuum sealing film (Mylar). A new method, which is called optimization of the beam quality, was put forward in this paper, in order to get smaller diameter of beam-spot in microbeam system.
基金The project supported by the National Science Foundation of in Anhui Province,China(No.01046201)
文摘The Experiments, methods and results of obtaining micron beam in the Microbeam Facility of the Institute of Plasma Physics were discussed in this paper. The H+2 beam was accelerated by the Van de GraafF electrostatic accelerator, and the collimator at the end of the beam line is a 60 μm thick stainless steel chip. And as a result, particle tracks on the solid track probes (CR39 film) etched in the solution of NaOH showed that the beam can go through the collimator with a small aperure (2000, 300, 55, 30, or 10 μm) and 3.5 μm thick vacuum film (Mylar). Besides the CR39 method, the beam was measured by an energy spectrum detector after the 10 μm diameter aperture and the 3.5 μm thick vacuum film too.
基金supported by National Natural Science Foundation of China(No.12135015)the Users with Excellence Program of Hefei Science Center,CAS(No.2021HSCUE012)+3 种基金the National Key R&D Program of China(No.2022Y FE03010003)the Major Science and Technology Infrastructure Maintenance and Reconstruction Projects of the Chinese Academy of Sciences 2021the Special Funds for Improving Conditions for Scientific Research in National Scientific Institutions 2022the China Scholarship Council。
文摘At the EAST tokamak, the ion temperature(T_(i)) is observed to be clamped around 1.25 keV in electron cyclotron resonance(ECR)-heated plasmas, even at core electron temperatures up to 10 keV(depending on the ECR heating power and the plasma density). This clamping results from the lack of direct ion heating and high levels of turbulence-driven transport. Turbulent transport analysis shows that trapped electron mode and electron temperature gradient-driven modes are the most unstable modes in the core of ECR-heated H-mode plasmas. Nevertheless, recently it was found that the T_(i)/T_(e)ratio can increase further with the fraction of the neutral beam injection(NBI) power, which leads to a higher core ion temperature(Ti0). In NBI heating-dominant H-mode plasmas, the ion temperature gradient-driven modes become the most unstable modes.Furthermore, a strong and broad internal transport barrier(ITB) can form at the plasma core in high-power NBI-heated H-mode plasmas when the T_(i)/T_(e)ratio approaches ~1, which results in steep core Teand Tiprofiles, as well as a peaked neprofile. Power balance analysis shows a weaker Teprofile stiffness after the formation of ITBs in the core plasma region, where Ticlamping is broken,and the core Tican increase further above 2 keV, which is 80% higher than the value of Ticlamping in ECR-heated plasmas. This finding proposes a possible solution to the problem of Ticlamping on EAST and demonstrates an advanced operational regime with the formation of a strong and broad ITB for future fusion plasmas dominated by electron heating.
基金supported by the Czech Science Foundation under project no.22-21122JPartial financial support from the Ministry of Health of the Czech Republic under the grant Nr.20-08-00150+2 种基金partial financial support from the Charles University Grant Agency under project number 389422partial financial support from the Science Grant Agency of the Slovak Republic through project No.1/0153/21faculty specific research project FSI-S-23-8340.
文摘This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SLM).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the SLM material and unmeasurably low porosity in the SPS material.The main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion resistance.Both materials showed comparable strength of∼110 MPa in tension and compression and relatively good deformability of∼9%and∼21%for the SLM and SPS materials,respectively.The corrosion resistance of the SPS material in 0.1 M NaCl solution was superior to the SLM one and comparable to the conventional extruded material.The digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the SLM material.On the other hand,one of the primary outcomes of this study is that the SPS consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.
基金partially supported by the National Natural Science Foundation of China (Grant Nos. 0204131240 and 11575067)the Shenzhen Municipal Collaborative Innovation Technology ProgramInternational Science and Technology (S&T) Cooperation Project (Grant No. GJHZ20220913142609017)the “Fourteenth Five-Year Plan” Basic Technological Research Project (Grant No. JSZL2022XXXX001)。
文摘Quasi-coherent micro-instabilities is one of the key topics of magnetic confinement fusion. This work focuses on the quasi-coherent spectra of ion temperature gradient(ITG) and trapped-electron-mode instabilities using newly developed far-forward collective scattering measurements within ohmic plasmas in the J-TEXT tokamak.The ITG mode is characterized by frequencies ranging from 30 to 100 k Hz and wavenumbers(k_(θρs)) less than 0.3. Beyond a critical plasma density threshold, the ITG mode undergoes a bifurcation, which is marked by a reduction in frequency and an enhancement in amplitude. Concurrently, enhancements in ion energy loss and degradation in confinement are observed. This ground-breaking discovery represents the first instance of direct experimental evidence that establishes a clear link between ITG instability and ion thermal transport.
基金This work is supported by the National MCF Energy R&D Program of China(Grant Nos.2018YFE0302100 and 2019YFE03010003)the National Natural Science Foundation of China(Grant Nos.12005264,12105322,and 12075285)+3 种基金the National Magnetic Confinement Fusion Science Program of China(Grant No.2022YFE03100003)the Natural Science Foundation of Anhui Province of China(Grant No.2108085QA38)the Chinese Postdoctoral Science Found(Grant No.2021000278)the Presidential Foundation of Hefei institutes of Physical Science(Grant No.YZJJ2021QN12).
文摘Multifaceted asymmetric radiation from the edge(MARFE) movement which can cause density limit disruption is often encountered during high density operation on many tokamaks. Therefore, identifying and predicting MARFE movement is meaningful to mitigate or avoid density limit disruption for the steady-state high-density plasma operation. A machine learning method named random forest(RF) has been used to predict the MARFE movement based on the density ramp-up experiment in the 2022’s first campaign of Experimental Advanced Superconducting Tokamak(EAST). The RF model shows that besides Greenwald fraction which is the ratio of plasma density and Greenwald density limit, dβp/dt,H98and d Wmhd/dt are relatively important parameters for MARFE-movement prediction. Applying the RF model on test discharges, the test results show that the successful alarm rate for MARFE movement causing density limit disruption reaches ~ 85% with a minimum alarm time of ~ 40 ms and mean alarm time of ~ 700 ms. At the same time, the false alarm rate for non-disruptive and non-density-limit disruptive discharges can be kept below 5%. These results provide a reference to the prediction of MARFE movement in high density plasmas, which can help the avoidance or mitigation of density limit disruption in future fusion reactors.
基金Project supported by the Research Foundation of Education Bureau of Hunan Province,China (Grant No.21B0648)the National Natural Science Foundation of China (Grant Nos.11805239,12075282,and 11775268)the Natural Science Foundation of Hunan Province,China (Grant No.2019JJ50011)。
文摘The linear behavior of the dominant unstable mode(m=2,n=1)and its high order harmonics(m=2n,n≥2)are numerically investigated in a reversed magnetic shear cylindrical plasma with two q=2 rational surfaces on the basis of the non-reduced magnetohydrodynamics(MHD)equations.The results show that with low beta(beta is defined as the ratio of plasma pressure to magnetic field pressure),the dominant mode is a classical double tearing mode(DTM).However,when the beta is sufficiently large,the mode is driven mainly by plasma pressure.In such a case,both the linear growth rate and mode structures are strongly affected by pressure,while almost independent of the resistivity.This means that the dominant mode undergoes a transition from DTM to pressure-driven mode with the increase of pressure,which is consistent with the experimental result in ASDEX Upgrade.The simulations also show that the distance between two rational surfaces has an important influence on the pressure needed in mode transition.The larger the distance between two rational surfaces,the larger the pressure for driving the mode transition is.Motivated by the phenomena that the high-m modes may dominate over low-m modes at small inter-resonance distance,the high-m modes with different pressures and q profiles are studied too.
基金supported by the National Key R&D Program of China(Nos.2017YFE0300500 and 2017YFE0300503)the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228).
文摘The investigation of electron cyclotron(EC)wave absorption and current drive has been performed for the China Fusion Engineering Test Reactor(CFETR)hybrid scenarios using the TORAY code.To achieve the physics goal of the EC system in CFETR,a total of four wave frequency values and nine locations of launching antennas have been considered,and the injection poloidal and toroidal angles have been scanned systematically.The electron cyclotron current drive(ECCD)efficiency of the 170 GHz EC system is quite low due to the wave-particle interactions being located at the low-field side.To optimize the ECCD efficiency,the wave frequency is increased up to 221–250 GHz,which leads to the power being deposited at the high-field side.The off-axis ECCD efficiency can be significantly enhanced by launching EC waves from the top window and injecting them towards the high-field side.The optimized ECCD efficiency atρ=0.32 and atρ=0.4 is 2.9 and 2.2 times that of 170 GHz,respectively.
基金supported by National Key R&D Program of China(Nos.2019YFE03050002,2018YFE0310400,and 2022YFE03040002)National Natural Science Foundation of China(Nos.12005003 and 11975270)Science Foundation of Institute of Plasma Physics,Chinese Academy of Sciences(No.DSJJ-2022-04)。
文摘High-order harmonics q(ψ_(s))=1 energetic particle modes(EPMs)have been observed in toroidal plasmas experiments with neutral beam injection.To investigate these phenomena,linear properties and nonlinear dynamics of these EPMs driven by passing energetic particles(EPs)are studied via the global hybrid kinetic-magnetohydrodynamic code M3D-K.Simulation results demonstrate that passing EPs'effects on high mode-number harmonics(q(ψ_(s))=m/n=2/2,3/3,4/4)instability are more obvious than the q(ψ_(s))=1/1 mode,especially when q-profile is sufficiently flat in the core region.Furthermore,the effects of the pitch angleΛ_0 and beam ion pressure P_(hot)/P_(total)on the features of high n components are also analyzed specifically.It is found that there exists only one resonant condition for these EPMs.In the nonlinear phase,these high mode-number harmonics can induce significant energetic ions redistribution and chirping up phenomena,which differs from the classical fishbone excited by passing EPs.These discoveries are conducive to better apprehend the underlying physical mechanisms of the highorder harmonics driven by passing EPs.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFE0301100 and 2022YFE03130000)the National Natural Science Foundation of China(Grant Nos.12105322,11905138,11905148,and 11905254)+5 种基金the Natural Science Foundation of Anhui Province of China(Grant No.2108085QA38)the Chinese Postdoctoral Science Found(Grant No.2021000278)the Presidential Foundation of Hefei Institutes of Physical Science(Grant No.YZJJ2021QN12)the U.S.Department of Energy contract DE-AC02–09CH11466(Grant No.DE-SC0016553)the Users with Excellence Program of Hefei Science Center CAS(Grant Nos.2020HSC-UE010 and 2021HSC-UE013)Interdisciplinary and Collaborative Teams of CAS.
文摘Massive gas injection(MGI)is a traditional plasma disruption mitigation method.This method directly injected massive gas into the pre-disruption plasma and had been developed on the Experimental Advanced Superconducting Tokamak(EAST).Different noble gas injection experiments,including He,Ne,and Ar,were performed to compare the mitigation effect of plasma disruption by evaluating the key parameters such as flight time,pre-thermal quench(pre-TQ),and current quench(CQ).The flight time was shorter for low atomic number(Z)gas,and the decrease in flight time by increasing the amount of gas was insignificant.However,both pre-TQ and CQ durations decreased considerably with the increase in gas injection amount.The effect of atomic mass on pre-TQ and CQ durations showed the opposite trend.The observed trend could help in controlling CQ duration in a reasonable area.Moreover,the analysis of radiation distribution with different impurity injections indicated that low Z impurity could reduce the asymmetry of radiation,which is valuable in mitigating plasma disruption.These results provided essential data support for plasma disruption mitigation on EAST and future fusion devices.
基金National Natural Science Foundation of China(Nos.11827810,11875177,12105189 and 12075155)International Atomic Energy Agency Research(No.22733)National Magnetic Confinement Fusion Program of China(No.2019YFE03010001)。
文摘A quasi-coherent(QC)mode was observed in the core region of low-density ohmic plasmas in Sino-UNIted Spherical Tokamak.In experiments on the QC mode,two sets of moveable Langmuir probes(LPs)were used to measure the local parameters including floating potential,electron temperature,electron density,and so on,as well as their profiles.To monitor the magnetohydrodynamic activities,a Mirnov probe was used to measure the poloidal magnetic fluctuation.The QC mode can be seen in the spectra of floating potential,but there is no similar peak in the spectra of magnetic fluctuation.Thus,the QC mode is probably electrostatic.By analyzing the electrostatic potential fluctuations from the LPs,the features of the QC mode including frequency,wavenumber,propagation direction,and dependence on collisionality are identified,which are consistent with the characteristics of dissipative trapped electron mode.
基金supported by National Natural Sciences Foundation of China(Nos.12075052,12175034 and 12275098)National Key R&D Program of China(Nos.2018YFE0309103,2017YFE0301100 and 2017YFE0301104)。
文摘To better understand divertor detachment and asymmetry in the Experimental Advanced Superconducting Tokamak(EAST),drift modeling via the comprehensive edge plasma code SOLPS-ITER of neon impurity seeded plasmas in favorable/unfavorable toroidal magnetic field(BT)has been performed.Firstly,electrostatic potential/field(f/E)distribution has been analyzed,to make sure that f and E are correctly described and to better understand drift-driven processes.After that,drift effects on divertor detachment and asymmetry have been focused on.In accordance with the corresponding experimental observations,simulation results demonstrate that in favorable BTthe onset of detachment is highly asymmetric between the inner and outer divertors;and reversing BT can significantly decrease the magnitude of in-out asymmetry in the onset of detachment,physics reasons for which have been explored.It is found that,apart from the well-known E×B drift particle flow from one divertor to the other through the private flux region,scrape-off layer(SOL)heat flow,which is much more asymmetrically distributed between the high field side and low field side for favorable BTthan that for unfavorable B_T,is also a critical parameter affecting divertor detachment and asymmetry.During detachment,upstream pressure(P_u)reduction occurs and tends to be more dramatical in the colder side than that in the hotter side.The convective SOL heat flow,emerging due to in-out asymmetry in P_u reduction,is found to be critical for understanding divertor detachment and asymmetry observed in EAST.To better understand the calculated drastic power radiation in the core and upstream SOL,drift effects on divertor leakage/retention of neon in EAST with both BTdirections have been addressed for the first time,by analyzing profile of poloidal neon velocity and that of neon ionization source from atoms.This work can be a reference for future numeric simulations performed more closely related to experimental regimes.
基金the National Key R&D Program of China(Nos.2017YFE0300500 and 2017YFE0300503)the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228).
文摘A discharge with electron temperature up to 14 keV has been achieved in EAST.Analysis of the electron cyclotron current drive(ECCD)efficiency at high electron temperature under EAST parameters is presented using C3PO/LUKE code.Simulation results show that the ECCD efficiency of X-mode increases with central electron temperature up to 10 keV and then starts to decrease above 10 keV,at a specific magnetic field and toroidal angle.The efficiency degradation is due to the presence of the third harmonic extraordinary(X3)downshifted absorption at the low field side(LFS);even the cold resonance of X3 mode is located outside the plasma.As the electron temperature increases from 5 to 20 ke V,the X3 absorption increases from 0.9%to 96.4%.The trapping electron effect at the LFS produces a reverse Ohkawa current.The competition between the Fisch–Boozer current drive and the Ohkawa current drive results in a decrease in ECCD efficiency.ECCD efficiency optimization is achieved through two methods.One is to increase the toroidal angle,leading to X2 mode predominating again over X3 mode and the electron resonance domain of X2 mode moving far from the trapped/passing boundary.The second one is to increase the magnetic field to move away the X3 resonance layer from the plasma,hence less EC power absorbed by X3 mode.
基金supported jointly by National Natural Science Foundation of China(Nos.U20A20372,51807046,51777206)the Natural Science Foundation of Anhui Province(Nos.2108085MD136,1908085MA29)。
文摘Sulfamethoxazole(SMX)is an antibiotic and widely present in aquatic environments,so it presents a serious threat to human health and sustainable development.A dielectric barrier discharge(DBD)plasma jet was utilized to degrade aqueous SMX,and the effects of various operating parameters(working gas,discharge power,etc)on SMX degradation performance were studied.The experimental results showed that the DBD plasma jet can obtain a relatively high degradation efficiency for SMX when the discharge power is high with an oxygen atmosphere,the initial concentration of SMX is low,and the aqueous solution is under acidic conditions.The reactive species produced in the liquid phase were detected,and OH radicals and O3were found to play a significant role in the degradation of SMX.Moreover,the process of SMX degradation could be better fitted by the quasi-first-order reaction kinetic equation.The analysis of the SMX degradation process indicated that SMX was gradually decomposed and 4-amino benzene sulfonic acid,benzene sulfonamide,4-nitro SMX,and phenylsulfinyl acid were detected,and thus three possible degradation pathways were finally proposed.The mineralization degree of SMX reached 90.04%after plasma treatment for 20 min,and the toxicity of the solution fluctuated with the discharge time but eventually decreased.
文摘The erosion loss of cathode is essential for the lifetime of magnetoplasmadynamic thruster(MPDT).In this work,an endurance test system for MPDT cathodes was designed and developed,and the erosion characteristics,erosion rate and erosion mechanism of the cathode were studied using the system under vacuum condition.The WCe20 hollow cathode was selected to carry out the long-term erosion of 540 h with the argon propellant supply flow rate of40 ml min^(-1),the input current of 25 A,and the central magnetic field intensity of 96 Gs.In order to predict the theoretical service life of cathode,a steady state erosion numerical model was established.The calculation results show that the total erosion rate of sputtering and evaporation is 11.58 mg h^(-1),which is slightly smaller than the test data of the average cathode corrosion rate of 12.70 mg h^(-1) in the experiment,because the experimental value includes start-up erosion rate.
基金This work was carried out within the framework of the EUROfusion Consortium,funded by the European Union via the Euratom Research and Training Programme(Grant No.101052200-EUROfusion)Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the European Union or the European Commission.Neither the European Union nor the European Commission can be held responsible for them.The involved teams have operated within the framework of the Enabling Research Project:Grant No.ENR-IFE.01.CEA“Advancing shock ignition for direct-drive inertial fusion.”The work was also supported by the Natural Sciences and Engineering Research Council of Canada(Grant No.RGPIN-2019-05013)+5 种基金The authors acknowledge support of the PALS Infrastructure within the MŠMT(MEYS)project Grant No.LM2023068Staff members of the PALS Research Center appreciate financial support(Grant No.LM2023068)from the Czech Ministry of Education,Youth and Sports facilitating operation of the PALS facilityThe work of JIHT RAS team was supported by the Ministry of Science and Higher Education of the Russian Federation(State Assignment No.075-01129-23-00)The work at NRMU MEPhI was supported by the Ministry of Science and Higher Education of the Russian Federation(Agreement No.075-15-2021-1361)This project has received funding from the CNR funded Italian research Network ELI-Italy(D.M.No.63108.08.2016)This work was funded by United Kingdom EPSRC Grants No.EP/P026796/1 and No.EP/L01663X/1.The results presented in this paper are based on work carried out between September 2018 and December 2021.
文摘In an experiment carried out at the Prague Asterix Laser System at laser intensities relevant to shock ignition conditions(I>10^(16) W/cm^(2)),the heating and transport of hot electrons were studied by using several complementary diagnostics,i.e.,K_(α)time-resolved imaging,hard x-ray filtering(a bremsstrahlung cannon),and electron spectroscopy.Ablators with differing composition from low Z(parylene N)to high Z(nickel)were used in multilayer planar targets to produce plasmas with different coronal temperature and collisionality and modify the conditions of hot-electron generation.The variety of available diagnostics allowed full characterization of the population of hot electrons,retrieving their conversion efficiency,time generation and duration,temperature,and angular divergence.The obtained results are shown to be consistent with those from detailed simulations and similar inertial confinement fusion experiments.Based on the measured data,the advantages,reliability,and complementarity of the experimental diagnostics are discussed.
基金support of this work by the project‘ELI-LASERLAB Europe Synergy,Hi PER&IPERIONCH.gr’(MIS 5002735)which is implemented under the Action‘Reinforcement of the Research and Innovation Infrastructure’funded by the Operational Programme‘Competitiveness,Entrepreneurship and Innovation’(NSRF 2014–2020)+2 种基金co-financed by Greece and the European Union(European Regional Development Fund)supported by computational time granted from the Greek Research and Technology Network(GRNET)in the National HPC facility,ARIS,under project ID pr009023-La MIPla S IIIcofinanced by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness,Entrepreneurship,and Innovation,under the call Research–Create–Innovate(project code:T1EDK-04549,project title:Development of a coherent X-ray multispectral microscopy system)。
文摘The rapid development of high-intensity laser-generated particle and photon secondary sources has attracted widespread interest during the last 20 years not only due to fundamental science research but also because of the important applications of this developing technology.For instance,the generation of relativistic particle beams,betatron-type coherent X-ray radiation and high harmonic generation have attracted interest from various fields of science and technology owing to their diverse applications in biomedical,material science,energy,space,and security applications.In the field of biomedical applications in particular,laser-driven particle beams as well as laser-driven X-ray sources are a promising field of study.This article looks at the research being performed at the Institute of Plasma Physics and Lasers(IPPL)of the Hellenic Mediterranean University Research Centre.The recent installation of the ZEUS 45 TW laser system developed at IPPL offers unique opportunities for research in laser-driven particle and X-ray sources.This article provides information about the facility and describes initial experiments performed for establishing the baseline platforms for secondary plasma sources.
基金supported by the National Magnetic Confinement Fusion Energy R&D Program of China(Nos.2022YFE03030001,2022YFE03020004 and 2022YFE 03050003)National Natural Science Foundation of China(Nos.12275310,11975275,12175277 and 11975271)+2 种基金the Science Foundation of Institute of Plasma Physics,Chinese Academy of Sciences(No.DSJJ-2021-01)the Collaborative Innovation Program of Hefei Science Center,Chinese Academy of Sciences(No.2021HSC-CIP019)the Users with Excellence Program of Hefei Science Center,Chinese Academy of Sciences(Nos.2021HSC-UE014 and 2021HSCUE012)。
文摘A gas puff imaging(GPI)diagnostic has been developed and operated on EAST since 2012,and the time-delay estimation(TDE)method is used to derive the propagation velocity of fluctuations from the two-dimensional GPI data.However,with the TDE method it is difficult to analyze the data with fast transient events,such as edge-localized mode(ELM).Consequently,a method called the spatial displacement estimation(SDE)algorithm is developed to estimate the turbulence velocity with high temporal resolution.Based on the SDE algorithm,we make some improvements,including an adaptive median filter and super-resolution technology.After the development of the algorithm,a straight-line movement and a curved-line movement are used to test the accuracy of the algorithm,and the calculated speed agrees well with preset speed.This SDE algorithm is applied to the EAST GPI data analysis,and the derived propagation velocity of turbulence is consistent with that from the TDE method,but with much higher temporal resolution.
基金financially supported by National Natural Science Foundation of China(No.12127809)。
文摘Measurement of plasma electron density by far-infrared laser polarimetry has become a routine and indispensable tool in magnetic confinement fusion research.This article presents the design of a Cotton-Mouton polarimeter interferometer,which provides a reliable density measurement without fringe jumps.Cotton-Mouton effect on Experimental Advanced Superconducting Tokamak(EAST)is studied by Stokes equation with three parameters(s_(1),s_(2),s_(3)).It demonstrates that under the condition of a small Cotton-Mouton effect,parameter s_(2)contains information about Cotton-Mouton effect which is proportional to the line-integrated density.For a typical EAST plasma,the magnitude of Cotton-Mouton effects is less than 2πfor laser wavelength of 432μm.Refractive effect due to density gradient is calculated to be negligible.Time modulation of Stokes parameters(s_(2),s_(3))provides heterodyne measurement.Due to the instabilities arising from laser oscillation and beam refraction in plasmas,it is necessary for the system to be insensitive to variations in the amplitude of the detection signal.Furthermore,it is shown that non-equal amplitude of X-mode and O-mode within a certain range only affects the DC offset of Stokes parameters(s_(2),s_(3))but does not greatly influence the phase measurements of Cotton-Mouton effects.
基金Project supported by the National MCF Energy Research and Development Program of China (Grant Nos.2022YFE03010002,2018YFE0302100,and 2018YFE0301105)the National Natural Science Foundation of China (Grant Nos.11875291,11805236,11905256,and 12075285)。
文摘Plasma equilibrium reconstruction provides essential information for tokamak operation and physical analysis.An extensive and reliable set of magnetic diagnostics is required to obtain accurate plasma equilibrium.This study designs and optimizes the magnetic diagnostics layout for the reconstruction of the equilibrium of the plasma according to the scientific objectives,engineering design parameters,and limitations of the Chinese Fusion Engineering Test Reactor(CFETR).Based on the CFETR discharge simulation,magnetic measurement data are employed to reconstruct consistent plasma equilibrium parameters,and magnetic diagnostics'number and position are optimized by truncated Singular value decomposition,verifying the redundancy reliability of the magnetic diagnostics layout design.This provides a design solution for the layout of the magnetic diagnostics system required to control the plasma equilibrium of CFETR,and the developed design and optimization method can provide effective support to design magnetic diagnostics systems for future magnetic confinement fusion devices.