Under investigation in this paper is a generalized(3+1)-dimensional Kadomtsev-Petviashvili equation in fluid dynamics and plasma physics.Soliton and one-periodic-wave solutions are obtained via the Hirota bilinear met...Under investigation in this paper is a generalized(3+1)-dimensional Kadomtsev-Petviashvili equation in fluid dynamics and plasma physics.Soliton and one-periodic-wave solutions are obtained via the Hirota bilinear method and Hirota-Riemann method.Magnitude and velocity of the one soliton are derived.Graphs are presented to discuss the solitons and one-periodic waves:the coefficients in the equation can determine the velocity components of the one soliton,but cannot alter the soliton magnitude;the interaction between the two solitons is elastic;the coefficients in the equation can influence the periods and velocities of the periodic waves.Relation between the one-soliton solution and one-periodic wave solution is investigated.展开更多
The extraction of traveling wave solutions for nonlinear evolution equations is a challenge in various mathematics,physics,and engineering disciplines.This article intends to analyze several traveling wave solutions f...The extraction of traveling wave solutions for nonlinear evolution equations is a challenge in various mathematics,physics,and engineering disciplines.This article intends to analyze several traveling wave solutions for themodified regularized long-wave(MRLW)equation using several approaches,namely,the generalized algebraic method,the Jacobian elliptic functions technique,and the improved Q-expansion strategy.We successfully obtain analytical solutions consisting of rational,trigonometric,and hyperbolic structures.The adaptive moving mesh technique is applied to approximate the numerical solution of the proposed equation.The adaptive moving mesh method evenly distributes the points on the high error areas.This method perfectly and strongly reduces the error.We compare the constructed exact and numerical results to ensure the reliability and validity of the methods used.To better understand the considered equation’s physical meaning,we present some 2D and 3D figures.The exact and numerical approaches are efficient,powerful,and versatile for establishing novel bright,dark,bell-kink-type,and periodic traveling wave solutions for nonlinear PDEs.展开更多
Plasma technology has widespread applications in many fields, whereas the methods for manipulating plasma transport are limited to magnetic control. In this study, we used a simplified diffusion-migration approach to ...Plasma technology has widespread applications in many fields, whereas the methods for manipulating plasma transport are limited to magnetic control. In this study, we used a simplified diffusion-migration approach to describe plasma transport. The feasibility of the transformation theory for plasma transport was demonstrated.As potential applications, we designed three model devices capable of cloaking, concentrating, and rotating plasmas without disturbing the density profile of plasmas in the background. This research may help advance plasma technology in practical fields, such as medicine and chemistry.展开更多
The late Academician Professor CAI Shidong was an outstanding plasma physicist who had made seminal contributions in both fundamental plasma theories and controlled thermonuclear fusion energy research. Professor CAI ...The late Academician Professor CAI Shidong was an outstanding plasma physicist who had made seminal contributions in both fundamental plasma theories and controlled thermonuclear fusion energy research. Professor CAI was also one of the pioneers in China＇s plasma physics research. In 1973, Professor CAI decided to leave U.S.展开更多
In this paper,the dust particle surface potential for argon-helium plasma is evaluated analytically and numerically in the context of negatively charged dust particles by employing a power-law(r,q)-distribution functi...In this paper,the dust particle surface potential for argon-helium plasma is evaluated analytically and numerically in the context of negatively charged dust particles by employing a power-law(r,q)-distribution function.Recent studies have reported the argon-helium plasma and conducted a brief theoretical and experimental survey.To deepen our understanding further,this study aims to analyze the argon-helium plasma comprehensively using the same pattern but with the(r,q)-distribution function.For this purpose,the current balance equations are derived for electron,helium and argon ions,when these charge species attain the quasineutrality condition.We numerically examined the currents of plasma species for a broad range of effective distribution function parameters r and q.It is revealed that the surface potential of dust particles is significantly affected by the parameters r and q,helium ion-to-electron temperature ratio,argon ion-to-electron temperature ratio,and helium ion to argon ion number density ratio.By incorporating the multi-ion(argon-helium)species,the significance of low-temperature nonMaxwellian dusty(complex)plasma is briefly examined.展开更多
X-ray sources with tunable energy spectra have a wide range of applications in different scenarios due to their different penetration depths.However,existing x-ray sources face difficulties in terms of energy regulati...X-ray sources with tunable energy spectra have a wide range of applications in different scenarios due to their different penetration depths.However,existing x-ray sources face difficulties in terms of energy regulation.In this paper,we present a scheme for tuning the energy spectrum of a betatron x-ray generated from a relativistic electron bunch oscillating in a plasma wakefield.The center energy of the x-ray source can be tuned from several keV to several hundred keV by changing the plasma density,thereby extending the control range by an order of magnitude.At different central energies,the brightness of the betatron radiation is in the range of 3.7×10^(22)to 5.5×10^(22)photons/(0.1%BW·s·mm^(2)·mrad^(2))and the photon divergence angle is about 2 mrad.This high-brightness,energy-controlled betatron source could pave the way to a wide range of applications requiring photons of specific energy,such as phase-contrast imaging in medicine,non-destructive testing and material analysis in industry,and imaging in nuclear physics.展开更多
High-power laser systems have opened new frontiers in scientifi research and have revolutionized various scientifi fields offering unprecedented capabilities for understanding fundamental physics and allowing unique a...High-power laser systems have opened new frontiers in scientifi research and have revolutionized various scientifi fields offering unprecedented capabilities for understanding fundamental physics and allowing unique applications.This paper details the successful commissioning of the 1 PW experimental area at the Extreme Light Infrastructure–Nuclear Physics(ELI-NP)facility in Romania,using both of the available laser arms.The experimental setup featured a short focal parabolic mirror to accelerate protons through the target normal sheath acceleration mechanism.Detailed experiments were conducted using various metallic and diamond-like carbon targets to investigate the dependence of the proton acceleration on different laser parameters.Furthermore,the paper discusses the critical role of the laser temporal profil in optimizing proton acceleration,supported by hydrodynamic simulations that are correlated with experimental outcomes.The finding underscore the potential of the ELI-NP facility to advance research in laser–plasma physics and contribute significantl to high-energy physics applications.The results of this commissioning establish a strong foundation for experiments by future users.展开更多
Technological miniaturization has enabled the development of small satellites weighing as little as 1 kg.Unfortunately,there is still a lack of suitable efficient micropropulsion systems at these scales.The pulsed pla...Technological miniaturization has enabled the development of small satellites weighing as little as 1 kg.Unfortunately,there is still a lack of suitable efficient micropropulsion systems at these scales.The pulsed plasma thruster is a structurally simple form of electric propulsion.This simplicity also makes it ideally suited for miniaturization.Its history can be traced back to applications in satellites that are much larger than micro/nano-satellites.The vast majority of modern pulsed plasma thrusters use solid polytetrafluoroethylene(PTFE)as a propellant.Unfortunately,at lower discharge energy levels such as those necessitated by the power limitations of micro/nano-satellites,PTFE has a tendency to exhibit carbon deposition,which can ultimately lead to thruster failure.In this new era of small satellites,it is important to consider alternative propellants in the miniaturization of pulsed plasma thrusters.This brief review discusses the needs and limitations of small satellites and alternative propellants that may be able to meet these needs.Such propellants may be able to offer advantages such as a longer thruster lifetime,a higher specific impulse,or a higher thrust-topower ratio.This would enable the development of different types of pulsed plasma thrusters that can be tailored towards specific mission requirements.展开更多
Particle-in-cell (PIC) method has got much benefits from GPU-accelerated heterogeneous systems.However,the performance of PIC is constrained by the interpolation operations in the weighting process on GPU (graphic pro...Particle-in-cell (PIC) method has got much benefits from GPU-accelerated heterogeneous systems.However,the performance of PIC is constrained by the interpolation operations in the weighting process on GPU (graphic processing unit).Aiming at this problem,a fast weighting method for PIC simulation on GPU-accelerated systems was proposed to avoid the atomic memory operations during the weighting process.The method was implemented by taking advantage of GPU's thread synchronization mechanism and dividing the problem space properly.Moreover,software managed shared memory on the GPU was employed to buffer the intermediate data.The experimental results show that the method achieves speedups up to 3.5 times compared to previous works,and runs 20.08 times faster on one NVIDIA Tesla M2090 GPU compared to a single core of Intel Xeon X5670 CPU.展开更多
The travelling solutions of the Burgers equation may be used as the seed solutions. According to the fraction-type deforming relation between the Burgers equation and the plasma motion equation, some travelling soluti...The travelling solutions of the Burgers equation may be used as the seed solutions. According to the fraction-type deforming relation between the Burgers equation and the plasma motion equation, some travelling solutions of the plasma motion equation are achieved with this seed solutions as discussed in this paper.展开更多
Surface waves （SWs） in planar-type overdense plasmas are analyzed and the invariable SW mode caused by the resonant excitation of surface plasmon polaritons （SPPs） is presented. It is found that the electric field...Surface waves （SWs） in planar-type overdense plasmas are analyzed and the invariable SW mode caused by the resonant excitation of surface plasmon polaritons （SPPs） is presented. It is found that the electric field peaks at the location where the plasma density equals the cut-off density while the plasma density gradient and the collision rate have different influences on the field amplitude and the peak＇s width. Moreover, the mode conversion between SW of SPPs and electron plasma waves play a significant role in production of overdense plasma.展开更多
Quantum effects on Rayleigh-Taylor instability of a stratified incompressible plasmas layer under the influence of vertical magnetic field are investigated. The solutions of the linearized equations of motion together...Quantum effects on Rayleigh-Taylor instability of a stratified incompressible plasmas layer under the influence of vertical magnetic field are investigated. The solutions of the linearized equations of motion together with the boundary conditions lead to deriving the relation between square normalized growth rate and square normalized wave number in two algebraic equations and are numerically analyzed. In the case of the real solution of these two equations, they can be combined to generate a single equation. The results show that the presence of vertical magnetic field beside the quantum effect will bring about more stability on the growth rate of unstable configuration.展开更多
We utilize an interferometer to investigate the changes of the refractive index caused by dielectric barrier discharge plasma. The electronic density of the plasma produced is measured and analyzed tentatively. The re...We utilize an interferometer to investigate the changes of the refractive index caused by dielectric barrier discharge plasma. The electronic density of the plasma produced is measured and analyzed tentatively. The results show that density of the plasma increases linearly with exciting voltages.展开更多
The molecular dynamics （MD） method is used to simulate the interactions of energetic C20 clusters with the dense plasma targets within the framework of the linear Vlasov-Poisson theory. The influences of various clu...The molecular dynamics （MD） method is used to simulate the interactions of energetic C20 clusters with the dense plasma targets within the framework of the linear Vlasov-Poisson theory. The influences of various clusters （H2, N2, C20 and C60 respectively） on stopping power are discussed. The simulation results show that the vicinage effects in the Coulomb explosion dynamics and the stopping power are strongly affected by the variations in the cluster speed and the plasma parameters. Coulomb explosions are found to proceed faster for higher speeds, lower plasma densities and higher electron temperatures. In addition, the cluster stopping power is strongly enhanced in the early stages of Coulomb explosions due to the vicinage effect, but this enhancement eventually diminishes, after the cluster constituent ions are sufficiently separated. For the large and heavy clusters, the stopping power ratio reaches much higher values in the early stage of Coulomb explosion owing to the constructive interferences in the vicinage effect.展开更多
A general,fast,and effective approach is developed for numerical calculation of kinetic plasma linear dispersion relations.The plasma dispersion function is approximated by J-pole expansion.Subsequently,the dispersion...A general,fast,and effective approach is developed for numerical calculation of kinetic plasma linear dispersion relations.The plasma dispersion function is approximated by J-pole expansion.Subsequently,the dispersion relation is transformed to a standard matrix eigenvalue problem of an equivalent linear system.Numerical solutions for the least damped or fastest growing modes using an 8-pole expansion are generally accurate;more strongly damped modes are less accurate,but are less likely to be of physical interest.In contrast to conventional approaches,such as Newton＇s iterative method,this approach can give either all the solutions in the system or a few solutions around the initial guess.It is also free from convergence problems.The approach is demonstrated for electrostatic dispersion equations with one-dimensional and twodimensional wavevectors,and for electromagnetic kinetic magnetized plasma dispersion relation for bi-Maxwellian distribution with relative parallel velocity flows between species.展开更多
The physical process of capillary discharge in a PE tube utilized in electro-thermal-chemical(ETC)guns was investigated.ETC guns can enhance the ignition and combustion of propellant in order to reduce the ignition de...The physical process of capillary discharge in a PE tube utilized in electro-thermal-chemical(ETC)guns was investigated.ETC guns can enhance the ignition and combustion of propellant in order to reduce the ignition delay and increase muzzle velocity of the projectile.A key component in ETC gun is the capillary plasma source.In this paper,a 2D steady state model of discharge was built by using magnetic hydrodynamics method.It took the plasma energy balance,material ablation,mass and momentum conservations in a quasi-neutral plasma region into account.Also,the effect of different compositions and PE concentration distribution were considered.In order to evaluate the validation of this model,the simulation results are compared with former works.展开更多
The plasma temperature of the semiconductor bridge (SCB) was measured in real-time according to relative intensity ratio of dual lines of atomic emission spectrum.The plasma temperature under different discharge pulse...The plasma temperature of the semiconductor bridge (SCB) was measured in real-time according to relative intensity ratio of dual lines of atomic emission spectrum.The plasma temperature under different discharge pulses and the influence of discharge pulse energy on it were studied.The results show that the plasma peak temperature rises gradually with the increase of initial discharging voltage and charging capacitance.For the capacitance of 22 μF,if the initial discharging voltage increases from 21 V to 63 V,the plasma peak temperature rises from 2 000 K to 6 200 K.For the discharging voltage of 39 V,the peak temperature rises from 2 200 K to 3 800 K when the capacitance increases from 6.8 μF to 100 μF.The change of pulse discharge has a very small effect on the plasma temperature at the late time discharge (LTD).In view of the change of plasma temperature with the pulse energy,the discharging voltage has a greater effect on the plasma temperature than the capacitance.The results provide some experimental basis for the further research on SCB ignition and detonation mechanisms.展开更多
Freestanding hemispherical diamond films have been fabricated by microwave plasma chemical vapor deposition using graphite and molybdenum （Mo） as substrates. Characterized by Raman spectroscopy and scanning electron...Freestanding hemispherical diamond films have been fabricated by microwave plasma chemical vapor deposition using graphite and molybdenum （Mo） as substrates. Characterized by Raman spectroscopy and scanning electron microscopy, the crystalline quality of the films deposited on Mo is higher than that on graphite, which is attributed to the difference in intrinsic properties of the two substrates. By decreasing the methane concentration, the diamond films grown on the Mo substrate vary from black to white, and the optical transparency is enhanced. After polishing the growth side, the diamond films show an infrared transmittance of 35-60% in the range 400-4000 cm^- 1.展开更多
The effects of working pressure on the composition, structure and surface morphology properties of CuInSe2 （CIS） films selenized with a plasma-assisted selenization process is investigated. Higher selenium content, ...The effects of working pressure on the composition, structure and surface morphology properties of CuInSe2 （CIS） films selenized with a plasma-assisted selenization process is investigated. Higher selenium content, better crystalline quality and much more regular surface particles compared to the others are found in the CIS film with 40 Pa working pressure. A Cu（In,Ga）Se2 device fabricated with the optimized plasma-assisted selenization process is demonstrated to be better than our previous result. After discussion, the reason for these phenomena is attributed to the compromise of electron temperature and plasma density.展开更多
A three-dimensional numerical model of laser-arc hybrid plasma for aluminum alloy fillet joints is developed in this study.This mod-el accounts for the geometric complexity of fillet joints,the physical properties of ...A three-dimensional numerical model of laser-arc hybrid plasma for aluminum alloy fillet joints is developed in this study.This mod-el accounts for the geometric complexity of fillet joints,the physical properties of shielding gases with varying He-Ar ratios,and the coupling between arc plasma and laser-induced metal plume.The accuracy of the model is validated using a high-speed camera.The effects of varying He contents in the shielding gas on both the temperature and flow velocity of hybrid plasma,as well as the distribu-tion of laser-induced metal vapor mass,were investigated separately.The maximum temperature and size of arc plasma decrease as the He volume ratio increases,the arc distribution becomes more concentrated,and its flow velocity initially decreases and then sharply increases.At high helium content,both the flow velocity of hybrid plasma and metal vapor are high,the metal vapor is con-centrated on the right side of keyhole,and its flow appears chaotic.The flow state of arc plasma is most stable when the shielding gas consists of 50%He+50%Ar.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.11272023by the Fundamental Research Funds for the Central Universities under Grant No.50100002016105010。
文摘Under investigation in this paper is a generalized(3+1)-dimensional Kadomtsev-Petviashvili equation in fluid dynamics and plasma physics.Soliton and one-periodic-wave solutions are obtained via the Hirota bilinear method and Hirota-Riemann method.Magnitude and velocity of the one soliton are derived.Graphs are presented to discuss the solitons and one-periodic waves:the coefficients in the equation can determine the velocity components of the one soliton,but cannot alter the soliton magnitude;the interaction between the two solitons is elastic;the coefficients in the equation can influence the periods and velocities of the periodic waves.Relation between the one-soliton solution and one-periodic wave solution is investigated.
文摘The extraction of traveling wave solutions for nonlinear evolution equations is a challenge in various mathematics,physics,and engineering disciplines.This article intends to analyze several traveling wave solutions for themodified regularized long-wave(MRLW)equation using several approaches,namely,the generalized algebraic method,the Jacobian elliptic functions technique,and the improved Q-expansion strategy.We successfully obtain analytical solutions consisting of rational,trigonometric,and hyperbolic structures.The adaptive moving mesh technique is applied to approximate the numerical solution of the proposed equation.The adaptive moving mesh method evenly distributes the points on the high error areas.This method perfectly and strongly reduces the error.We compare the constructed exact and numerical results to ensure the reliability and validity of the methods used.To better understand the considered equation’s physical meaning,we present some 2D and 3D figures.The exact and numerical approaches are efficient,powerful,and versatile for establishing novel bright,dark,bell-kink-type,and periodic traveling wave solutions for nonlinear PDEs.
基金financial support from the National Natural Science Foundation of China (Grant Nos. 11725521 and 12035004)the Science and Technology Commission of Shanghai Municipality (Grant No. 20JC1414700)。
文摘Plasma technology has widespread applications in many fields, whereas the methods for manipulating plasma transport are limited to magnetic control. In this study, we used a simplified diffusion-migration approach to describe plasma transport. The feasibility of the transformation theory for plasma transport was demonstrated.As potential applications, we designed three model devices capable of cloaking, concentrating, and rotating plasmas without disturbing the density profile of plasmas in the background. This research may help advance plasma technology in practical fields, such as medicine and chemistry.
文摘The late Academician Professor CAI Shidong was an outstanding plasma physicist who had made seminal contributions in both fundamental plasma theories and controlled thermonuclear fusion energy research. Professor CAI was also one of the pioneers in China＇s plasma physics research. In 1973, Professor CAI decided to leave U.S.
文摘In this paper,the dust particle surface potential for argon-helium plasma is evaluated analytically and numerically in the context of negatively charged dust particles by employing a power-law(r,q)-distribution function.Recent studies have reported the argon-helium plasma and conducted a brief theoretical and experimental survey.To deepen our understanding further,this study aims to analyze the argon-helium plasma comprehensively using the same pattern but with the(r,q)-distribution function.For this purpose,the current balance equations are derived for electron,helium and argon ions,when these charge species attain the quasineutrality condition.We numerically examined the currents of plasma species for a broad range of effective distribution function parameters r and q.It is revealed that the surface potential of dust particles is significantly affected by the parameters r and q,helium ion-to-electron temperature ratio,argon ion-to-electron temperature ratio,and helium ion to argon ion number density ratio.By incorporating the multi-ion(argon-helium)species,the significance of low-temperature nonMaxwellian dusty(complex)plasma is briefly examined.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11921006 and 12175058)the Beijing Distinguished Young Scientist Program and National Grand Instrument Project (Grant No.SQ2019YFF01014400)+1 种基金the Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park (Grant No.Z231100006023003)in part funded by United Kingdom EPSRC (Grant Nos.EP/G054950/1,EP/G056803/1,EP/G055165/1,and EP/M022463/1)。
文摘X-ray sources with tunable energy spectra have a wide range of applications in different scenarios due to their different penetration depths.However,existing x-ray sources face difficulties in terms of energy regulation.In this paper,we present a scheme for tuning the energy spectrum of a betatron x-ray generated from a relativistic electron bunch oscillating in a plasma wakefield.The center energy of the x-ray source can be tuned from several keV to several hundred keV by changing the plasma density,thereby extending the control range by an order of magnitude.At different central energies,the brightness of the betatron radiation is in the range of 3.7×10^(22)to 5.5×10^(22)photons/(0.1%BW·s·mm^(2)·mrad^(2))and the photon divergence angle is about 2 mrad.This high-brightness,energy-controlled betatron source could pave the way to a wide range of applications requiring photons of specific energy,such as phase-contrast imaging in medicine,non-destructive testing and material analysis in industry,and imaging in nuclear physics.
基金supported by the Extreme Light Infrastructure–Nuclear Physics(ELI-NP)PhaseⅡa project co-finance by the Romanian Government and the European Union through the European Regional Development Fund,by the Romanian Ministry of Education and Research CNCS-UEFISCDI(Project No.PN-ⅡIP4-IDPCCF-2016-0164)+1 种基金Nucleu Projects(Grant No.PN 23210105 and 19060105)supports ELI-NP through IOSIN funds as a Facility of National Interest。
文摘High-power laser systems have opened new frontiers in scientifi research and have revolutionized various scientifi fields offering unprecedented capabilities for understanding fundamental physics and allowing unique applications.This paper details the successful commissioning of the 1 PW experimental area at the Extreme Light Infrastructure–Nuclear Physics(ELI-NP)facility in Romania,using both of the available laser arms.The experimental setup featured a short focal parabolic mirror to accelerate protons through the target normal sheath acceleration mechanism.Detailed experiments were conducted using various metallic and diamond-like carbon targets to investigate the dependence of the proton acceleration on different laser parameters.Furthermore,the paper discusses the critical role of the laser temporal profil in optimizing proton acceleration,supported by hydrodynamic simulations that are correlated with experimental outcomes.The finding underscore the potential of the ELI-NP facility to advance research in laser–plasma physics and contribute significantl to high-energy physics applications.The results of this commissioning establish a strong foundation for experiments by future users.
基金supported by the National Natural Science Foundation of China(No.11802022)the Beijing Institute of Technology Research Fund Program for Young Scholars。
文摘Technological miniaturization has enabled the development of small satellites weighing as little as 1 kg.Unfortunately,there is still a lack of suitable efficient micropropulsion systems at these scales.The pulsed plasma thruster is a structurally simple form of electric propulsion.This simplicity also makes it ideally suited for miniaturization.Its history can be traced back to applications in satellites that are much larger than micro/nano-satellites.The vast majority of modern pulsed plasma thrusters use solid polytetrafluoroethylene(PTFE)as a propellant.Unfortunately,at lower discharge energy levels such as those necessitated by the power limitations of micro/nano-satellites,PTFE has a tendency to exhibit carbon deposition,which can ultimately lead to thruster failure.In this new era of small satellites,it is important to consider alternative propellants in the miniaturization of pulsed plasma thrusters.This brief review discusses the needs and limitations of small satellites and alternative propellants that may be able to meet these needs.Such propellants may be able to offer advantages such as a longer thruster lifetime,a higher specific impulse,or a higher thrust-topower ratio.This would enable the development of different types of pulsed plasma thrusters that can be tailored towards specific mission requirements.
基金Projects(61170049,60903044)supported by National Natural Science Foundation of ChinaProject(2012AA010903)supported by National High Technology Research and Development Program of China
文摘Particle-in-cell (PIC) method has got much benefits from GPU-accelerated heterogeneous systems.However,the performance of PIC is constrained by the interpolation operations in the weighting process on GPU (graphic processing unit).Aiming at this problem,a fast weighting method for PIC simulation on GPU-accelerated systems was proposed to avoid the atomic memory operations during the weighting process.The method was implemented by taking advantage of GPU's thread synchronization mechanism and dividing the problem space properly.Moreover,software managed shared memory on the GPU was employed to buffer the intermediate data.The experimental results show that the method achieves speedups up to 3.5 times compared to previous works,and runs 20.08 times faster on one NVIDIA Tesla M2090 GPU compared to a single core of Intel Xeon X5670 CPU.
文摘The travelling solutions of the Burgers equation may be used as the seed solutions. According to the fraction-type deforming relation between the Burgers equation and the plasma motion equation, some travelling solutions of the plasma motion equation are achieved with this seed solutions as discussed in this paper.
文摘Surface waves （SWs） in planar-type overdense plasmas are analyzed and the invariable SW mode caused by the resonant excitation of surface plasmon polaritons （SPPs） is presented. It is found that the electric field peaks at the location where the plasma density equals the cut-off density while the plasma density gradient and the collision rate have different influences on the field amplitude and the peak＇s width. Moreover, the mode conversion between SW of SPPs and electron plasma waves play a significant role in production of overdense plasma.
文摘Quantum effects on Rayleigh-Taylor instability of a stratified incompressible plasmas layer under the influence of vertical magnetic field are investigated. The solutions of the linearized equations of motion together with the boundary conditions lead to deriving the relation between square normalized growth rate and square normalized wave number in two algebraic equations and are numerically analyzed. In the case of the real solution of these two equations, they can be combined to generate a single equation. The results show that the presence of vertical magnetic field beside the quantum effect will bring about more stability on the growth rate of unstable configuration.
基金Supported by the National Natural Science Foundation of China under Grant No 50776086.
文摘We utilize an interferometer to investigate the changes of the refractive index caused by dielectric barrier discharge plasma. The electronic density of the plasma produced is measured and analyzed tentatively. The results show that density of the plasma increases linearly with exciting voltages.
基金Supported by the National Natural Science Foundation of China under Grant No 10705007, and the Doctorial Start-up Foundation of Liaoning Province under Grant No 20071067.
文摘The molecular dynamics （MD） method is used to simulate the interactions of energetic C20 clusters with the dense plasma targets within the framework of the linear Vlasov-Poisson theory. The influences of various clusters （H2, N2, C20 and C60 respectively） on stopping power are discussed. The simulation results show that the vicinage effects in the Coulomb explosion dynamics and the stopping power are strongly affected by the variations in the cluster speed and the plasma parameters. Coulomb explosions are found to proceed faster for higher speeds, lower plasma densities and higher electron temperatures. In addition, the cluster stopping power is strongly enhanced in the early stages of Coulomb explosions due to the vicinage effect, but this enhancement eventually diminishes, after the cluster constituent ions are sufficiently separated. For the large and heavy clusters, the stopping power ratio reaches much higher values in the early stage of Coulomb explosion owing to the constructive interferences in the vicinage effect.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2015GB110003,2011GB105001,2013GB111000)National Natural Science Foundation of China(No.91130031)the Recruitment Program of Global Youth Experts
文摘A general,fast,and effective approach is developed for numerical calculation of kinetic plasma linear dispersion relations.The plasma dispersion function is approximated by J-pole expansion.Subsequently,the dispersion relation is transformed to a standard matrix eigenvalue problem of an equivalent linear system.Numerical solutions for the least damped or fastest growing modes using an 8-pole expansion are generally accurate;more strongly damped modes are less accurate,but are less likely to be of physical interest.In contrast to conventional approaches,such as Newton＇s iterative method,this approach can give either all the solutions in the system or a few solutions around the initial guess.It is also free from convergence problems.The approach is demonstrated for electrostatic dispersion equations with one-dimensional and twodimensional wavevectors,and for electromagnetic kinetic magnetized plasma dispersion relation for bi-Maxwellian distribution with relative parallel velocity flows between species.
文摘The physical process of capillary discharge in a PE tube utilized in electro-thermal-chemical(ETC)guns was investigated.ETC guns can enhance the ignition and combustion of propellant in order to reduce the ignition delay and increase muzzle velocity of the projectile.A key component in ETC gun is the capillary plasma source.In this paper,a 2D steady state model of discharge was built by using magnetic hydrodynamics method.It took the plasma energy balance,material ablation,mass and momentum conservations in a quasi-neutral plasma region into account.Also,the effect of different compositions and PE concentration distribution were considered.In order to evaluate the validation of this model,the simulation results are compared with former works.
基金Sponsored by the Anhui Province Colleges Young Talents Fund(2011SQRL121)
文摘The plasma temperature of the semiconductor bridge (SCB) was measured in real-time according to relative intensity ratio of dual lines of atomic emission spectrum.The plasma temperature under different discharge pulses and the influence of discharge pulse energy on it were studied.The results show that the plasma peak temperature rises gradually with the increase of initial discharging voltage and charging capacitance.For the capacitance of 22 μF,if the initial discharging voltage increases from 21 V to 63 V,the plasma peak temperature rises from 2 000 K to 6 200 K.For the discharging voltage of 39 V,the peak temperature rises from 2 200 K to 3 800 K when the capacitance increases from 6.8 μF to 100 μF.The change of pulse discharge has a very small effect on the plasma temperature at the late time discharge (LTD).In view of the change of plasma temperature with the pulse energy,the discharging voltage has a greater effect on the plasma temperature than the capacitance.The results provide some experimental basis for the further research on SCB ignition and detonation mechanisms.
基金Supported by the Program for New Century Excellent Talents in University （NCET）, the National Natural Science Foundation of China under Grant No 50772041.
文摘Freestanding hemispherical diamond films have been fabricated by microwave plasma chemical vapor deposition using graphite and molybdenum （Mo） as substrates. Characterized by Raman spectroscopy and scanning electron microscopy, the crystalline quality of the films deposited on Mo is higher than that on graphite, which is attributed to the difference in intrinsic properties of the two substrates. By decreasing the methane concentration, the diamond films grown on the Mo substrate vary from black to white, and the optical transparency is enhanced. After polishing the growth side, the diamond films show an infrared transmittance of 35-60% in the range 400-4000 cm^- 1.
基金Supported by the National High-Tech Research and Development Program of China under Grant No 2004AA513020, the National Natural Science Foundation of China under Grant No 60906033, and the Specialized Research Fund for the Doctoral Program of Higher Education （00800551008）
文摘The effects of working pressure on the composition, structure and surface morphology properties of CuInSe2 （CIS） films selenized with a plasma-assisted selenization process is investigated. Higher selenium content, better crystalline quality and much more regular surface particles compared to the others are found in the CIS film with 40 Pa working pressure. A Cu（In,Ga）Se2 device fabricated with the optimized plasma-assisted selenization process is demonstrated to be better than our previous result. After discussion, the reason for these phenomena is attributed to the compromise of electron temperature and plasma density.
基金supported by the National Natural Science Foundation of China(Grant No.52375340,51975263,52405366).
文摘A three-dimensional numerical model of laser-arc hybrid plasma for aluminum alloy fillet joints is developed in this study.This mod-el accounts for the geometric complexity of fillet joints,the physical properties of shielding gases with varying He-Ar ratios,and the coupling between arc plasma and laser-induced metal plume.The accuracy of the model is validated using a high-speed camera.The effects of varying He contents in the shielding gas on both the temperature and flow velocity of hybrid plasma,as well as the distribu-tion of laser-induced metal vapor mass,were investigated separately.The maximum temperature and size of arc plasma decrease as the He volume ratio increases,the arc distribution becomes more concentrated,and its flow velocity initially decreases and then sharply increases.At high helium content,both the flow velocity of hybrid plasma and metal vapor are high,the metal vapor is con-centrated on the right side of keyhole,and its flow appears chaotic.The flow state of arc plasma is most stable when the shielding gas consists of 50%He+50%Ar.
