检索结果-南通市图书馆

Successive particle acceleration by use of two tightly focused ultra-short intense laser pulses

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2006年第3期15卷 568-574页

作者：陈民盛政明张杰 Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

We suggest a scheme of electron acceleration by use of two tightly focused ultra-short intense laser pulses at a IOOTW level. Electroas obtain a preliminary acceleration with a small angular spread by the longitudinal ponderomotive force of the first pulse. They are then injected and further accelerated to hundreds of MeV by the second laser pulse.

关键词： laser acceleration particle acceleration plasmas

Two-stage acceleration of interstellar ions driven by high-energy lepton plasma flows

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2015年第10期58卷 76-80页

作者： CUI YunQian SHENG ZhengMing LU QuanMing LI YuTong ZHANG Jie Beijing National Laboratory of Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Scottish Universities Physics Alliance Department of Physics University of Strathclyde Key Laboratory for Laser Plasmas (Mo E) and Department of Physics and Astronomy Shanghai Jiao Tong University IFSA Collaborative Innovation Center Shanghai Jiao Tong University School of Earth and Space Sciences University of Science and Technology of China

We present the particle-in-cell(PIC) simulation results of the interaction of a high-energy lepton plasma flow with background electron-proton plasma and focus on the acceleration processes of the protons. It is found that the acceleration follows a two-stage process. In the first stage, protons are significantly accelerated transversely(perpendicular to the lepton flow) by the turbulent magnetic field "islands" generated via the strong Weibel-type instabilities. The accelerated protons shows a perfect inverse-power energy spectrum. As the interaction continues, a shockwave structure forms and the protons in front of the shockwave are reflected at twice of the shock speed, resulting in a quasi-monoenergetic peak located near 200 Me V under the simulation parameters. The presented scenario of ion acceleration may be relevant to cosmic-ray generation in some astrophysical environments.

关键词： particle acceleration Fermi acceleration collisionless shock lepton plasma flow

Observation of Influence of Nucleons＇ Motion on Kaons Collective Flow in Dense Medium

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2010年第1期27卷 92-95页

作者：邢永忠郑玉明王艳艳张林屈世显 College of Physics and Information Technology Shaanxi Normal University Xi'an 710062 Department of Physics Tianshui Normal University Tianshui 741000 China Institute of Atomic Energy PO Box 275(18) Beijing 102413

In order to extract the information of the momentum-dependent interaction of kaons under the extreme condition, the properties of the positively charged kaons produced in a heavy ion collision are studied via a simple model which has an invariable nucleon＇s velocity. Our special attention is focused on the observation of the dependence of the kaon＇s properties on the motion of nucleons in a hot and dense nuclear environment. Starting from two kinds of kaon quasiparticle models defined in transport theories for simulating heavy ion collisions, we calculate the effective mass and potential of the K＋＇s produced in the collisions and find that these properties not only depend closely on the velocity of nucleons but the dependence varies with kaon＇s quasiparticle model. It is clearly shown that the motion of nucleons reduces the momentum of K＋＇s at a given rapidity and thus weakens the rapidity distribution of K＋＇s directed flow in realistic nuclear collisions.

关键词： particle acceleration KAONS TRANSPORT theory (Mathematics) HEAVY ion collisions QUASIparticleS (Physics) EFFECTIVE mass (Physics) NUCLEAR models

Accelerating Generalized Polygon Beams and Their Propagation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2015年第1期32卷 63-66页

作者：张云天张志刚程腾张青川伍小平 CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of China

Accelerating beams with intensity cusps and exotic topological properties are drawing increasing attention as they have extensive uses in many intriguing fields. We investigate the structural features of accelerating polygon beams, show their generalized mathematical form theoretically, and discuss the even-numbered polygon beams. Furthermore, we also carry out the experiment and observe the intensity evolution during their propagation.

关键词： particle acceleration GENERALIZED polygons THEORY of wave motion TOPOLOGY STRUCTURAL analysis (Engineering)

Electron acceleration by Beating of Two Intense Cross-Focused Hollow Gaussian Laser Beams in Plasma

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2018年第1期69卷 86-94页

作者： Saleh T. Mahmoud Rakhi Gauniyal Nafis Ahmad Priyanka Rawat Gunjan Purohit Department of Physics College of Science UAE University Laser Plasma Computational Laboratory Department of Physics DAV (PG) College

This paper presents propagation of two cross-focused intense hollow Gaussian laser beams(HGBs) in collisionless plasma and its effect on the generation of electron plasma wave(EPW) and electron acceleration process,when relativistic and ponderomotive nonlinearities are simultaneously operative. Nonlinear differential equations have been set up for beamwidth of laser beams, power of generated EPW, and energy gain by electrons using WKB and paraxial approximations. Numerical simulations have been carried out to investigate the effect of typical laser-plasma parameters on the focusing of laser beams in plasmas and further its effect on power of excited EPW and acceleration of electrons. It is observed that focusing of two laser beams in plasma increases for higher order of hollow Gaussian beams,which significantly enhanced the power of generated EPW and energy gain. The amplitude of EPW and energy gain by electrons is found to enhance with an increase in the intensity of laser beams and plasma density. This study will be useful to plasma beat wave accelerator and in other applications requiring multiple laser beams.

关键词： hollow Gaussian beams (HGBs) collisionless plasma cross-focusing electron plasma wave particle acceleration

A possible explanation of the knee of cosmic light component spectrum from 100 TeV to 3 PeV

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2017年第10期41卷 110-114页

作者：林文慧鲍必文姜泽军张力 Department of Astronomy Yunnan University Key Laboratory of Astroparticle physics of Yunnan Province Kunming 650091 China

A mixed hydrogen and helium（H ＋ He） spectrum with a clear steepening at ~700 TeV has been detected by the ARGO-YBJ experiments. In this paper, we demonstrate that the observed H ＋ He spectrum can be reproduced well with a model of cosmic rays escaping from the supernova remnants（SNRs） in our Galaxy. In this model, particles are accelerated in a SNR through a non-linear diffusive shock acceleration mechanism. Three components of high energy light nuclei escaped from the SNR are considered. It should be noted that the proton spectrum observed by KASCADE can be also explained by this model given a higher acceleration efficiency.

关键词： cosmic Rays particle acceleration supernova remnants amplified magnetic field

A computational study on the optical shaping of gas targets via blast wave collisions for magnetic vortex acceleration

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2022年第5期10卷 35-49页

作者： I.Tazes S.Passalidis E.Kaselouris I.Fitilis M.Bakarezos N.A.Papadogiannis M.Tatarakis V.Dimitriou Institute of Plasma Physics and Lasers-IPPL Hellenic Mediterranean University Research CentreRethymnonGreece Department of Electronic Engineering Hellenic Mediterranean UniversityChaniaGreece CNRS Laboratoire de Chimie Physique-Matière et RayonnementSorbonne UniversitéParisFrance Department of Music Technology and Acoustics Hellenic Mediterranean UniversityRethymnonGreece

This research work emphasizes the capability of delivering optically shaped targets through the interaction of nanosecond laser pulses with high-density gas-jet profiles,and explores proton acceleration in the near-critical density regime via magnetic vortex acceleration(MVA).Multiple blast waves(BWs)are generated by laser pulses that compress the gas-jet into near-critical steep gradient slabs of a few micrometres *** alternatives for delivering the laser pulses into the gas target are explored to efficiently control the characteristics of the density *** shock front collisions of the generated BWs are computationally studied by 3D magnetohydrodynamic *** efficiency of the proposed target shaping method for MVA is demonstrated for TW-class lasers by a particle-in-cell simulation.

关键词： blast waves particle acceleration magnetic vortex acceleration MHD simulations PIC simulations

Optimal injection scheme for electron acceleration by a tightly focused laser beam

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2005年第7期14卷 1407-1412页

作者：陈民盛政明张杰 LaboratoryofOpticalPhysics InstituteofPhysicsChineseAcademyofSclencesBeijlng100080China

Electron dynamics and energy gain in a tightly focused laser beam in vacuum are investigated by numerical simulations. There exist two acceleration mechanisms, i.e. acceleration by the longitudinal field or by the transverse field, which corresponds to two different trajectories. The relationship between the energy gain and the injection parameters of electrons, including the injection angle and momentum, is shown. For given laser parameters, the optimum injection parameters can be obtained.

关键词： laser acceleration particle acceleration plasmas energy gain

Laser wakefield accelerator modelling with variational neural networks

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2023年第1期11卷 67-74页

作者： M.J.V.Streeter C.Colgan C.C.Cobo C.Arran E.E.Los R.Watt N.Bourgeois L.Calvin J.Carderelli N.Cavanagh S.J.D.Dann R.Fitzgarrald E.Gerstmayr A.S.Joglekar B.Kettle P.Mckenna C.D.Murphy Z.Najmudin P.Parsons Q.Qian P.P.Rajeev C.P.Ridgers D.R.Symes A.G.R.Thomas G.Sarri S.P.D.Mangles School of Mathematics and Physics Queen’s University BelfastBelfastUK The John Adams Institute for Accelerator Science Imperial College LondonLondonUK York Plasma Institute School of PhysicsEngineering and TechnologyUniversity of YorkYorkUK Central Laser Facility STFC Rutherford Appleton LaboratoryDidcotUK Gérard Mourou Center for Ultrafast Optical Science University of MichiganAnn ArborUSA Ergodic LLC San FranciscoUSA Department of Physics SUPAUniversity of StrathclydeGlasgowUK

A machine learning model was created to predict the electron spectrum generated by a GeV-class laser wakefield *** model was constructed from variational convolutional neural networks,which mapped the results of secondary laser and plasma diagnostics to the generated electron *** ensemble of trained networks was used to predict the electron spectrum and to provide an estimation of the uncertainty of that *** is anticipated that this approach will be useful for inferring the electron spectrum prior to undergoing any process that can alter or destroy the *** addition,the model provides insight into the scaling of electron beam properties due to stochastic fluctuations in the laser energy and plasma electron density.

关键词： laser plasma interactions particle acceleration neural networks machine learning