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Electromagnetic radiation from laser wakefields in underdense plasma

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High Power Laser Science and Engineering 2014年第1期2卷 29-33页

作者： Yue Liu Wei-Min Wang zheng-ming sheng Key Laboratory for Laser Plasmas (MoE) and Department of Physics and Astronomy Shanghai Jiao Tong University Beijing National Laboratory of Condensed Matter Physics Institute of Physics CAS Department of Physics SUPA Strathclyde University

It is demonstrated by simulations and analysis that a wakefield driven by an ultrashort intense laser pulse in underdense plasma can emit tunable electromagnetic radiation along the laser propagation direction. The profile of such a kind of radiation is closely associated with the structure of the laser wakefield. In general, electromagnetic radiation in the terahertz range with its frequency a few times the electron plasma frequency can be generated in the moderate intensity regime. In the highly nonlinear case, a chain of radiation pulses is formed corresponding to the nonlinear structure of the wake. Study shows that the radiation is associated with the self-modulation process of the laser pulse in the wakefield and resulting transverse electron momenta from modulated asymmetric laser fields.

关键词： laser wakefield PIC simulation tunable radiation transverse momentum

Vlasov-Fokker-Planck Simulations for High-Power Laser-Plasma Interactions

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Communications in Computational Physics 2012年第4期11卷 1236-1260页

作者： Su-ming Weng zheng-ming sheng Hui Xu Jie Zhang Beijing National Laboratory of Condensed Matter Physics Institute of PhysicsCASBeijing 100190China Key Laboratory for Laser Plasmas(MoE)and Department of Physics Shanghai Jiaotong UniversityShanghai 200240China Theoretical Quantum Electronics(TQE) Technische Universit¨at DarmstadtD-64289 DarmstadtGermany Shandong Provincial Key Laboratory of Laser Polarization and Information Technology Department of PhysicsQufu Normal UniversityQufu 273165China

A review is presented on our recent Vlasov-Fokker-Planck(VFP)simulation code development and applications for high-power laser-plasma *** schemes are described for solving the kinetic VFP equation with both electronelectron and electron-ion collisions in one-spatial and two-velocity(1D2V)*** are based on the positive and flux conservation method and the finite volume method,and these twomethods can insure the particle number *** simulation code can deal with problems in high-power laser/beam-plasma interactions,where highly non-Maxwellian electron distribution functions usually develop and the widely-used perturbation theories with the weak anisotropy assumption of the electron distribution function are no longer in *** present some new results on three typical problems:firstly the plasma current generation in strong direct current electric fields beyond Spitzer-H¨arm’s transport theory,secondly the inverse bremsstrahlung absorption at high laser intensity beyond Langdon’s theory,and thirdly the heat transport with steep temperature and/or density gradients in laser-produced ***,numerical parameters,performance,the particle number conservation,and the energy conservation in these simulations are provided.

关键词： Vlasov-Fokker-Planck equation electric conductivity inverse bremsstrahlung nonlocal heat transport positive and flux conservation method finite volume method

Simulation of High Power THz Emission from Laser Interaction with Tenuous Plasma and Gas Targets

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Communications in Computational Physics 2008年第10期4卷 1258-1278页

作者： zheng-ming sheng Hui-Chun Wu Wei-MinWang Min Chen Xiao-Gang Dong Jun zheng Jie Zhang Department of Physics Shanghai Jiao Tong UniversityShanghai 200240China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsCASBeijing 100190China Max-Planck-Institut f¨ur Quanenoptik D-85748 GarchingGermany

With one-and two-dimensional particle-in-cell(PIC)codes,we simulate the generation of high power terahertz(THz)emission from the interaction of ultrashort intense lasers with tenuous plasma and gas *** driving high-amplitude electron plasma waves either with a laser wakefield or the beatwave of two laser pulses,powerful THz electromagnetic pulses can be produced by linear mode conversion in inhomogeneous plasma or by the transient current induced at the surfaces of a thin plasma layer of few plasma *** with incident lasers at moderate intensity such as 1017W/cm2,the produced emission can be at the level of tens of MW in power and capable of affording field strengths of a few MV/cm,suitable for the studies of THz nonlinear *** field ionization included in the PIC codes,THz emission from laser interaction with tenuous gas targets is *** is found that the transient transverse current formed during the ionization processes is responsible for the THz *** this mechanism,onemay also obtain THz fields ofMV/cm at lower laser intensity as compared with the schemes of plasma-wave excitation.

关键词： Particle-in-cell simulation laser-plasma electron plasma wave high power THz emission

Generation of single-cycle relativistic infrared pulses at wavelengths above 20 μm from density-tailored plasmas

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Matter and Radiation at Extremes 2022年第1期7卷 29-34页

作者： Xing-Long Zhu Wei-Yuan Liu Su-ming Weng Min Chen zheng-ming sheng Jie Zhang Key Laboratory for Laser Plasmas(MOE) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Tsung-Dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFSA Shanghai Jiao Tong UniversityShanghai 200240China SUPA Department of PhysicsUniversity of StrathclydeGlasgow G40NGUnited Kingdom

Ultra-intense short-pulse light sources are powerful tools for a wide range of ***,relativistic short-pulse lasers are normally generated in the near-infrared ***,we present a promising and efficient way to generate tunable relativistic ultrashort pulses with wavelengths above 20μm in a density-tailored *** this approach,in the first stage,an intense drive laser first excites a nonlinear wake in an underdense plasma,and its photon frequency is then downshifted via phase modulation as it propagates in the plasma ***,in the second stage,the drive pulse enters a lower-density plasma region so that the wake has a larger plasma cavity in which longer-wavelength infrared pulses can be *** simulations show that the resulting near-single-cycle pulses cover a broad spectral range of 10–40μm with a conversion efficiency of∼2.1%(∼34 mJ pulse energy).This enables the investigation of nonlinear infrared optics in the relativistic regime and offers new possibilities for the investigation of ultrafast phenomena and physics in strong fields.

关键词： relativistic regime intense

An Efficient Optimization Design Framework for Low-Resistance Shape of Bionic Amphibious Robot

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China Ocean Engineering 2024年第1期38卷 117-128页

作者： ZHANG Dai-yu ZHANG Man-yu WANG Zhi-dong zheng Wen-sheng LING Hong-jie HU Jun-ming School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

To realize the low-resistance shape optimization design of amphibious robots,an efficient optimization design framework is proposed to improve the geometric deformation flexibility and optimization *** the proposed framework,the free-form deformation parametric model of the flat slender body is established and an analytical calculation method for the height constraints is *** method is introduced to carry out the high-precision resistance calculation and a constrained Kriging-based optimization method is built to improve the optimization efficiency by circularly infilling the new sample points which satisfying the ***,the shape of an amphibious robot example is optimized to get the low-resistance shape and the results demonstrate that the presented optimization design framework has the advantages of simplicity,flexibility and high efficiency.

关键词： amphibious robot optimization method free-form deformation CFD-based hydrodynamic calculation

Post-solitons and electron vortices generated by femtosecond intense laser interacting with uniform near-critical-density plasmas

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Chinese Physics B 2022年第4期31卷 486-492页

作者： Dong-Ning Yue Min Chen Yao Zhao Pan-Fei Geng Xiao-Hui Yuan Quan-Li Dong zheng-ming sheng Jie Zhang School of Sciences Harbin Institute of Technology at WeihaiWeihai 264209China Key Laboratory for Laser Plasmas(Ministry of Education) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFSA Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of High Power Laser and Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Tsung-Dao Lee Institute Shanghai 200240China

Generation of nonlinear structures,such as stimulated Raman side scattering waves,post-solitons and electron vortices,during ultra-short intense laser pulse transportation in near-critical-density(NCD)plasmas is studied by using multidimensional particle-in-cell(PIC)*** two-dimensional geometries,both P-and S-polarized laser pulses are used to drive these nonlinear structures and to check the polarization effects on *** the S-polarized case,the scattered waves can be captured by surrounding plasmas leading to the generation of post-solitons,while the main pulse excites convective electric currents leading to the formation of electron vortices through Kelvin-Helmholtz instability(KHI).In the P-polarized case,the scattered waves dissipate their energy by heating surrounding *** vortices are excited due to the hosing instability of the drive *** polarization dependent physical processes are reproduced in two different planes perpendicular to the laser propagation direction in three-dimensional simulation with linearly polarized laser *** current work provides inspiration for future experiments of laser-NCD plasma interactions.

关键词： stimulated Raman side scattering near-critical-density plasmas electron vortices post-solitons

An empirical model for high energy density lithium-(ion)batteries with ultra-thick electrodes

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Tungsten 2024年第1期6卷 230-237页

作者： Li-ming Jin Guang-Guang Xing Nan Qin Yan-Yan Lu Jun-sheng zheng Cun-Man Zhang Jim P.zheng School of Automotive Studies and Clean Energy Automotive Engineering Center Tongji UniversityShanghai 201804China Department of Electrical Engineering University at BuffaloThe State University of New YorkBuffaloNY 14260USA

Increasing the electrode thickness is a significant method to decrease the weight and volume ratio of the inactive components for high energy density of the *** this contribution,we extracted a repeating unit in the configurations and establish the empirical energy density model based on some *** this model,the effects of the electrode thickness on the energy density for lithium-ion batteries(LIBs),lithium metal batteries(LMBs),and anode-free lithium batteries(ALBs)are evaluated quantitively with the current parameters of the *** results demonstrate that the structure evolutions from LIBs,LMBs to ALBs with the reduction of the anode weight contribution,the energy density can be well improved *** the increase of the thickness of the electrode provide another route to furthe r enhance the energydensity by decreasing the weight contribution of inactive materials;meanwhile the effects for ALBs are higher than LMBs and LIBs due to the higher weight ratio of inactive *** empirical energy density model is also applied into the practical system and provide intuitional results to guide the battery design for higher energy density.

关键词： Empirical model High energy density Lithium batteries Ultra-thick electrodes

Unconventional Fluorescent and Multi-responsive Polyethyleneimine with LCST and UCST Behavior:Synthesis,Characterization and Biological Applications

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Chinese Journal of Polymer Science 2024年第6期42卷 826-837页

作者： Feng-ming Yin Li-Li Wu Shu-sheng Li Xiao-Na Pan Xiao-Li Zhu Xu-Bao Jiang Xiang zheng Kong College of Chemistry and Chemical Engineering University of JinanJinan250022China Shandong Institute for Product Quality Inspection Jinan250102China College of Chemical Engineering Tianjin UniversityTianjin300072China

Non-aromatic fluorescent and multi-responsive materials,exhibiting inherent fluorescence emission and controlled phase change,have garnered significant attention in recent ***,the underlying interaction between their fluorescent properties and phase transition remains *** this study,we synthesized a series of catalyst-free aza-Michael addition-based polyethyleneimine(RFPEI)materials by reacting polyethyleneimine(PEI)with N-isopropyl acrylamide(NIPAM).The resulting RFPEI was comprehensively characterized,and demonstrated dual-phase transition behavior(LCST and UCST)in water,which could be finely tuned by adjusting its composition or external factors such as ***,upon UV irradiation(365 nm),RFPEI exhibited strong fluorescence *** further investigated the effects of NIPAM grafting percentage to PEI,polymer concentration,and pH on the LCST/UCST and fluorescent properties of RFPEI aqueous ***,we showcased the great potential of RFPEI as a versatile tool for physiological cell imaging,trace detection,and controlled release of *** study presents a novel class of stimuli-responsive fluorescent materials with promising applications in the field of biomedicine.

关键词： Polyethyleneimine Multi-responsiveness Intrinsic fluorescence emission Cell imaging Controlled drug release

Applications of mercury stable isotopes for tracing volcanism in the geologic record

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Science China Earth Sciences 2024年第5期67卷 1436-1458页

作者： Qing GONG ming-Xing LING Wang zheng State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China School of Earth System Science Institute of Surface-Earth System ScienceTianjin UniversityTianjin 300072China

Mercury(Hg)enrichments in ancient sediments have been used as a proxy of volcanism,especially large igneous province(LIP)***,considering the existence of other potential Hg sources besides volcanoes and the diverse factors(e.g.,organic matters,clay minerals,sulfide minerals and Fe oxides)that can affect Hg sequestration,there are considerable uncertainties to simply regard sedimentary Hg anomalies as signatures of volcanic *** stable isotopes,a promising tool for tracing the origins and transformations of Hg,have been increasingly used for determining the causes of Hg spikes and understanding the geochemical behavior of Hg in the geologic *** date,lots of researches have applied Hg concentrations and Hg isotopes to identify LIP volcanisms linking with significant geological events such as mass extinctions,ocean anoxic events and other environmental perturbations that mainly occurred in the ***,the results in previous studies clearly show that not all Hg enrichments are derived from volcanic inputs,which emphasize the need for more caution in using Hg as a fingerprint of *** a better understanding of Hg isotopes in the future,there will be important implications for Hg isotopes to reconstruct volcanic activities in the rock records and their impacts on biological evolution.

关键词： Mercury stable isotopes Large igneous province Mass extinction event Ocean anoxic event