在相对论性激光-等离子体系统中初始物理参数对激光脉冲的影响

基于相对论性激光-等离子体动力学理论，研究了相对论性激光-等离子体系统中圆偏振入射脉冲激光和等离子体相互作用对激光脉冲宽度的影响. 具体分析了在不同初始物理参数下脉冲激光的脉冲宽度在等离子体传播过程中的变化情况，重点分析了激光脉冲在等离子中压缩. 计算结果表明增加入射激光的强度和入射脉冲宽度以及减小等离子体的初始密度，能够有效地实现脉冲宽度在等离子体中压缩；当激光脉冲的初始参数a₀=0.12和τ=70以及等离子体密度n₀=0.3时，脉冲宽度相对压缩T/τ接近于1/10，从而给出了激光压缩的理论优化参数. 关键词：相对论性激光-等离子体激光脉冲宽度等离子体密度自压缩

The influence of initial physical parameters on laser pulse in the relativistic laser-plasma system

The present paper studies the influence of the interaction of incident pulsed laser and cold plasmas on the laser pulse in the relativistic laser-plasma system, taking the electron density fluctuation into account. For different initial parameters, the change of the laser-pulse width is analyzed in detail. The self-compression of the laser pulse is particularly discussed. Numerical calculation demonstrates that the pulse self-compression can be effectively achieved with the increase of the intensity and width of the laser pulse and the decrease of background plasma density. For initial laser-pulse parameters a₀=0.12 and τ=70 and plasma density n₀＝0.3, the ratio of compressed laser pulse to initial one is near to 1/10. And hence optimized theoretical parameters for the self-compression of the laser pulse are given.