共查询到18条相似文献,搜索用时 109 毫秒
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激光等离子体加速器能够在cm尺度内产生GeV量级的高品质电子束,为研制台式化自由电子激光提供驱动源。但是受限于激光等离子体加速中的难点和现有技术发展,电子束的品质难以达到自由电子激光的需求,尤其在稳定性、发散角和能散等方面,阻碍了台式化自由电子激光的研制。介绍了基于激光等离子体加速器的自由电子激光的最新进展,整理了目前高增益自由电子激光实验过程中存在的主要挑战和对应的解决方案与实验进展,并展望未来的发展方向。最近的研究结果证明,通过控制和优化激光等离子体加速器的注入和加速过程产生的高品质电子束可以在指数增益区域实现自发辐射放大,产生高增益的辐射,这也推动基于激光等离子体加速器的自由电子激光研究进入了一个新的阶段。 相似文献
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研究了不同能量的纳秒激光脉冲聚焦到单晶硅片上时,激光等离子体的自由电子密度和温度以及损伤形貌随激光脉冲能量增加的变化规律。研究结果表明:激光脉冲击穿硅介质产生的激光等离子体的体积以及自由电子密度和温度大小,决定了硅表面损伤的形貌特点和大小。自由电子密度和温度的变化特点是:随着激光脉冲能量的增加,激光等离子体的体积不断增大,自由电子温度缓慢增加而密度基本不变。又由于激光等离子体的自由电子密度和温度呈现从中心到边缘由大到小的变化趋势,所以损伤形貌总的特点是内部区域的熔化非常充分,形成明显的周期性排列的规则条纹,且条纹的排列趋势呈现环状;中部区域熔化不充分,形成条纹不很规则;边缘区域处分界明显,有时出现等离子体产生喷溅变色痕迹。 相似文献
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本文用磁流体理论研究了柱形波导填充等离子体的切伦柯夫自由电子激光器,表明该系统比普通切伦柯夫自由电子激光具有更高的工作频率和线性增长率。发现在入射电流和波导结构一定时,该系统和普通切伦柯夫自由电子激光器的增长率并不是随随电子束与介质的间距的增加而减小,而是存在一个最佳值。 相似文献
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建立了Compton型自由电子激光的准Dirac方程.用近似方法对方程进行了求解.由求得的电子波函数计算出电流密度表达式.结果表明,电子自旋影响着波函数及电流密度的分布
关键词: 相似文献
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超强激光在气体等离子体中传输时可以激发出大振幅的电子等离子体尾波。激光等离子体尾波加速器是利用该尾波对带电粒子(特别是电子和正电子)进行加速的一种新型装置。由于其加速梯度相较于现有的常规加速器可以提升1000倍,为建造超紧凑型的加速器和辐射源奠定了基础,也为将来建造基于等离子体的超高能正负电子对撞机和自由电子激光装置提供了可能。对该新型加速器的原理、特点、发展历程,尤其是近十年来的主要进展和未来发展趋势及面临的主要挑战进行简要梳理和介绍。 相似文献
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The wave function of a free electron in a laser plasma described via Riemannian geometry is derived by solving the Dirac equation in the associated curved space-time. If the laser field vanishes, the wave function naturally reduces to the case in flat space-time. 相似文献
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This paper presents an investigation of Stimulated Raman Scattering of gaussian laser beam in relativistic Plasma. The pump beam interacts with a pre-excited electron plasma wave and thereby generate a back-scattered wave. Due to intense laser beam, electron oscillatory velocity becomes comparable to the velocity of light, which modifies the background plasma density profile in a direction transverse to pump beam axis. The relativistic non-linearity due to increase in mass of the electrons effects the incident laser beam, electron plasma wave and back-scattered beam. We have set up the non-linear differential equations for the beam width parameters of the main beam, electron plasma wave, back-scattered wave and derived SRS back-reflectivity by taking full non-linear part of the dielectric constant of relativistic plasma with the help of moment theory approach. It is observed from the analysis that self-focusing of the pump beam greatly affects the SRS reflectivity, which plays a significant role in laser induced fusion. 相似文献
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This paper presents an investigation of self-focusing of Gaussian laser beam in collisionless plasma and its effect on stimulated Raman scattering process. The pump beam interacts with a pre-excited electron plasma wave thereby generating a back-scattered wave. On account of Gaussian intensity distribution of laser beam, the time independent component of the ponderomotive force along a direction perpendicular to the beam propagation becomes finite, which modifies the background plasma density profile in a direction transverse to pump beam axis. This modification in density affects the incident laser beam, electron plasma wave and back-scattered beam. We have set up the non-linear differential equations for the beam width parameters of the main beam, electron plasma wave, back-scattered wave and SRS-reflectivity by taking full non-linear part of the dielectric constant of collisionless plasma with the help of moment theory approach. It is observed from the analysis that focusing of waves greatly enhances the SRS reflectivity. 相似文献
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A method using expansion of the wave function in the basis of photonic and free atomic eigenstates is proposed for calculating the emission spectrum of an atom in a laser field. The wave function is constructed using the Kramers?Henneberger transformation so that the expression for the transition S matrix explicitly includes the nonlinear interaction with the laser field. The expansion coefficients are determined by the residual interaction, which depends on the coordinates of the classical free electron motion in the laser field. Resonances at the atomic transition frequencies explicitly arise in the emission spectrum when the residual interaction is considered in the first order. The numerical solution of the timedependent Schro¨ dinger equation for the hydrogen atom within the semiclassical approach is used to obtain emission spectra for laser pulses of different intensities and durations. 相似文献
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A surface plasma wave (SPW) over bismuth-vacuum interface has a signature of mass anisotropy of free electrons. For SPW propagation
along the trigonal axis there is no birefringence. The frequency cutoff of SPW
lies in the far infrared region and can be accessed using free electron laser. The damping rate of waves at low temperatures
is low. The surface plasma wave may be excited by an electron beam of current ∼100 mA propagating parallel to the interface
in its close proximity. 相似文献
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从考虑动理学效应的受激散射不稳定性的线性理论出发,对于n=2的Maxwell分布函数直到n=5的饱和情况的超高斯分布函数,计算了电子等离子体波和离子声波的频率和阻尼率。对受激喇曼散射和受激布里渊散射进行分析,结果表明,在激光高Z等离子体中,或者在具有激光热斑的中等Z等离子体中,电子等离子体波的阻尼率降低很多,离子声波的频率比Maxwell分布情况升高约15%。这些结果可和实验进行比较。 相似文献
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A set of moment relations, which can describe the charged fluids response to an intense pump laser, and a linearization substitution relation, which is more appropriate as compared with the past treatment, are given by theoretical analyses. The relevant equations of state (adiabatic and isothermal), momentum and energy equations are derived self-consistently.The dispersion relations of the electron plasma wave and the ion acoustic wave driven by an intense pump laser field are-obtained. The results show that the frequencies of both the excited electron plasma wave and the excited ion acoustic wave have a great modification in the case of strong pump. The former bears out the theoretical result obtained from Vlasov equation and the later is consistent with experimental observations. It is proved that the zero-frequency component of the laser light wave contribution to the plasma pressure tensor is un-neglected,which implies a greatly change to the wave excitation properties, particularly in the direction of parallel or approximately parallel to the laser field vector. 相似文献
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The propagation of light waves in an underdense plasma is studied using one-dimensional Vlasov-Maxwell numerical simulation.It is found that the light waves can be scattered by electron plasma waves as well as other heavily and weakly damping electron wave modes,corresponding to stimulated Raman and Brilluoin-like scatterings.The stimulated electron acoustic wave scattering is also observed as a high scattering level.High frequency plasma wave scattering is also observed.These electron electrostatic wave modes are due to a non-thermal electron distribution produced by the wave-particle interactions.The collision effects on stimulated electron acoustic wave and the laser intensity effects on the scattering spectra are also investigated. 相似文献