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Solitons and periodic waves for a generalized(3+1)-dimensional Kadomtsev-Petviashvili equation in fluid dynamics and plasma physics

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Communications in Theoretical physics 2020年第11期72卷 30-36页

作者： Dong Wang Yi-Tian Gao Cui-Cui Ding Cai-Yin Zhang Ministry-of-Education Key Laboratory of Fluid Mechanics and National Laboratory for Computational Fluid Dynamics Beijing University of Aeronautics and AstronauticsBeijing 100191China

Under investigation in this paper is a generalized(3+1)-dimensional Kadomtsev-Petviashvili equation in fluid dynamics and plasma *** and one-periodic-wave solutions are obtained via the Hirota bilinear method and Hirota-Riemann *** and velocity of the one soliton are *** 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 *** between the one-soliton solution and one-periodic wave solution is investigated.

关键词： fluid dynamics plasma physics generalized(3+1)-dimensional Kadomtsev-Petviashvili equation solitons periodic waves

Where physics meets chemistry： Thin film deposition from reactive plasmas

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Frontiers of Chemical Science and Engineering 2016年第4期10卷 441-458页

作者： Andrew Michelmore Jason D. Whittle James W. Bradley Robert D. Short School of Engineering University of South Australia Mawson Lakes Australia SA 5095 Future Industries Institute University of South Australia Mawson Lakes Australia SA 5095 Department of Electrical Engineering and Electronics University of Liverpool Liverpool L69 3GJ UK Material Science Institute Lancaster University Lancaster LA1 4YW UK

Functionalising surfaces using polymeric thin films is an industrially important field. One technique for achieving nanoscale, controlled surface functionalization is plasma deposition. plasma deposition has advantages over other surface engineering processes, including that it is solvent free, substrate and geometry independent, and the surface properties of the film can be designed by judicious choice of precursor and plasma conditions. Despite the utility of this method, the mechanisms of plasma polymer growth are generally unknown, and are usually described by chemical （i.e., radical） pathways. In this review, we aim to show that plasma physics drives the chemistry of the plasma phase, and surface-plasma interactions. For example, we show that ionic species can react in the plasma to form larger ions, and also arrive at surfaces with energies greater than 1000 kJ·mol^-1 （〉10 eV） and thus facilitate surface reactions that have not been taken into account previously. Thus, improving thin film deposition processes requires an understanding of both physical and chemical processes in plasma.

关键词： thin films plasma physics plasma chemistry,functionalization polymer

An application of the shortest path algorithm for the identification of weak MHD mode

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plasma Science and Technology 2023年第8期25卷 19-27页

作者：黄卓毛飞越丁永华田微黄名响李达沈呈硕王能超梁云峰 the J-TEXT Team College of Computer Science South-Central Minzu UniversityWuhan 430074People's Republic of China International Joint Research Laboratory of Magnetic Confinement Fusion and plasma physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China Forschungszentrum Jülich GmbH Institut für Energie-und Klimaforschung-PlasmaphysikPartner of the Trilateral Euregio Cluster(TEC)Jülich 52425Germany 不详

The identification of magnetohydrodynamic(MHD)modes is a crucial issue in the control of magnetically confined *** paper proposes a novel method for identifying the evolution of MHD modes from a signal with a low signal-to-noise *** proposed method generates a weighted directed graph from the time-frequency spectrum and calculates the evolution of the mode frequency by solving the shortest *** method addresses the limitations posed by the lack of data channels and the disturbance of noise in the estimation of mode frequency and yields much better results compared to traditional *** is demonstrated that,using this method,the evolution of an unlocked tearing mode was more accurately calculated on the J-TEXT *** method remains feasible even with a low signal-to-noise ratio of 0.5,as shown by its ***,with appropriate parameters,this method can be applied to not only signals with MHD modes,but also to general signals with continuous modes.

关键词： plasma physics magnetohydrodynamic pattern recognition

Tunable energy spectrum betatron x-ray sources in a plasma wakefield

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Chinese physics B 2024年第8期33卷 344-350页

作者：奚传易寿寅任韩立琦阿卜杜伍普尔·阿布力米提刘晓丹赵研英余金清 Hunan Provincial Key Laboratory of High-Energy Scale physics and Applications School of Physics and ElectronicsHunan UniversityChangsha 410082China Center for Relativistic Laser Science Institute for Basic ScienceGwangjuKorea State Key Laboratory of Nuclear physics and Technology and Key Laboratory of HEDP of the Ministry of EducationCAPTPeking UniversityBeijing 100871China

X-ray sources with tunable energy spectra have a wide range of applications in different scenarios due to their different penetration ***,existing x-ray sources face difficulties in terms of energy *** 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 *** 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 *** 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 *** 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.

关键词： betatron plasma physics x-ray plasma wakefield acceleration(PWFA)

Effect of Magnetic Field and Equilibrium Flow on Rayleigh-Taylor Instability

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Chinese physics Letters 2004年第10期21卷 2001-2004页

作者：吴征威张文禄李定杨维紘 DepartmentofModernphysics UniversityofScienceandTechnologyofChinaHefei230026

We investigate the effect of a finite equilibrium flow and magnetic field on the Rayleigh-Taylor instability. It is found that the equilibrium flow only makes a frequency shift of perturbation and the growth rate of the Rayleigh-Taylor instability remains unchanged. However, the magnetic field can change the growth rate and, in particular, a very strong magnetic field suppresses the growth rate.

关键词： plasma physics

Gaussian process tomography based on Bayesian data analysis for soft x-ray and AXUV diagnostics on EAST

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Chinese physics B 2020年第9期29卷 353-363页

作者： Yan Chao Liqing Xu Liqun Hu Yanmin Duan Tianbo Wang Yi Yuan Yongkuan Zhang Institute of plasma physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Southwestern Institute for physics CNNCChengdu 610200China

This work presents the Gaussian process tomography(GPT)based on Bayesian data analysis and its applications in soft x-ray(SXR)and absolute extreme ultraviolet spectroscopy(AXUV)diagnostics on experimental advanced superconducting tokamak(EAST).This is the first application of the GPT method in the AXUV diagnostic system in fusion *** is found that even if only horizontal detector arrays are used to reconstruct the two-dimensional(2D)distribution of SXR and AXUV emissivity fields,the GPT method performs robustly and extremely fast,which enables the GPT method to provide real-time feedback on impurity transport and fast magnetohydrodynamics(MHD)*** reconstructing SXR emissivity in the poloidal cross section on EAST,an m/n=1/1 internal kink mode has been observed,and the plasma redistribution due to the kink mode is clearly visible in the reconstructions,where m is the poloidal mode number and n is the toroidal mode ***-like internal disruptions extended throughout the entire plasma core and mainly driven by the m/n=2/1 mode have been *** the sawtooth-like internal disruption crash phase,the conversion from an m=2 mode to an m=1 mode is *** the reconstructed AXUV emissivity field we were able to observe the process of impurity accumulated in the plasma core and the mitigation of core impurity due to neon injection in the plasma *** data from all other diagnostics involved in the analysis shows that the reconstructions from AXUV measurements are reliable.

关键词： bayesian inference Gaussian process tomography plasma physics

Large Amplitude Low Frequency Waves in a Magnetized Nonuniform Electron-Positron-Ion plasma

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Chinese physics Letters 2004年第5期21卷 884-887页

作者： Q.Haque H.Saleem Abdus-SalamInternationalCentreforTheoreticalphysicsTrieste Italy Permanentaddresses:Departmentofphysics COMSATSInstituteofInformationTechnologyH-8IslamabadPakistan.

It is shown that the large amplitude low-frequency electromagnetic drift waves in electron–positron–ion plasmas might give rise to dipolar vortices. A linear dispersion relation of several coupled electrostatic and electromagnetic low-frequency modes is obtained. The relevance of this work to both laboratory and astrophysical situations is pointed out.

关键词： plasma physics

Unified treatment for accurate and fast evaluation of the Fermi-Dirac functions

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Chinese physics B 2010年第5期19卷 72-77页

作者： I.I.Guseinov B.A.Mamedov Department of physics Faculty of Arts and SciencesOnsekiz Mart UniversityCanakkaleTurkey Department of physics Faculty of Arts and SciencesGaziosmanpa sa UniversityTokatTurkey

A new analytical approach to the computation of the Fermi-Dirac （FD） functions is presented, which was suggested by previous experience with various algorithms. Using the binomial expansion theorem these functions are expressed through the binomial coefficients and familiar incomplete Gamma functions. This simplification and the use of the memory of the computer for the calculation of binomial coefficients may extend the limits to large arguments for users and result in speedier calculation, should such limits be required in practice. Some numerical results are presented for significant mapping examples and they are briefly discussed.

关键词： statistical semiconductors plasma physics nuclear physics

Magnetic Field Gradient and Curvature-Driven Drift Modes in Toroidal plasmas

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Chinese physics Letters 2004年第8期21卷 1575-1577页

作者：王爱科 H.Sanuki 董家齐 F.Zonca K.Itoh SouthwesternInstituteofphysics POBox432Chengdu610041 NationalInstituteforFusionScience TokiGifu509-5292Japan ENEAC.R.Frascati C.P.6500044FrascatiRomeItaly

A new kind of instability driven by the magnetic field gradient and curvature (MFGC) in toroidal plasmas is presented. It is found that the MFGC drift modes possess finite growth rates even if the plasma pressure gradient vanishes. In addition, the effects of plasma pressure gradient and safety factor on the MFGC modes have been analysed numerically.

关键词： plasma physics