超短脉冲激光产生等离子体通道寿命研究

Numerical study on prolonging lifetime of plasma channels generated by ultra-short laser pulses

利用强飞秒激光在大气中产生等离子体通道内带电粒子的动力学模型,综合考虑二体吸附、三体吸附、离解和复合等因素,分析后续激光退吸附作用对等离子体通道寿命的影响,给出有效延长通道寿命的后续激光控制参量。计算表明,选择不同的激光注入形式和注入时间,对通道寿命的延长有着不同的效果,适当优化的激光可以延长通道寿命达25μs以上。

The density and decay kinetics of a plasma channel produced in air by a self-guided intense femtosecond laser pulse is investigated by numerical simulation method. The two-body, three-body dissociation attachment and the recombination of the free electrons, positive and negative ions are considered in the theoretical model. The influence of dissociation attachment caused by the subsequently incident laser on the generated plasma channel has been studied and the effective control parameters of the subsequent laser can be obtained. The calculation shows that the lifetime of the channel is sensitive to the initial conditions of the subsequent laser and the relative delay between the subsequent laser and the maximum plasma density. The corresponding li- fetime of the revived plasma channel can be efficiently extended to more than 25μs, in the case that the subsequent laser is suffi- ciently controlled under optimum parameters.