组合脉冲激光铝等离子体的数值模拟研究

为了获得组合脉冲激光诱导等离子体光谱性能增强的物理机制, 基于FLASH程序模拟计算了预脉冲参数对组合脉冲激光诱导的铝等离子体参数时空分布的影响, 获得了在不同预脉冲波长和不同预主脉冲延时下产生的铝等离子体电子温度、电子密度和烧蚀质量的空间演化规律。结果表明, 在预主脉冲总能量相同的情况下, 随着预脉冲波长从0.266μm变化到1.064μm, 高温环境氦气等离子体羽辉的空间范围从0.7cm增大到3.0cm, 但组合脉冲对靶材的烧蚀效率严重下降, 而铝等离子体的最大电子温度保持稳定; 此外, 组合脉冲的时间延迟低于100ns。该研究可为组合脉冲激光诱导击穿等离子体光谱增强技术提供理论参考。

Numerical simulation of combined pulsed lasers aluminum plasma

In order to obtain the physical mechanism of the enhanced spectral performance of the combined pulse laser-induced plasma, the effects of pre-pulse parameters on the spatial and temporal distribution of parameters of the combined pulse laser-induced aluminum plasma were simulated based on the FLASH program. The spatial evolution of electron temperature, electron density, and ablative mass of aluminum plasma under different prepulse wavelength and different pre-pulse delay was obtained. The numerical simulation results show that the space range of helium plasma plume increases from 0.7cm to 3.0cm with the change of pre-pulse wavelength from 0.266μm to 1.064μm when the total energy of the pre-pulse is the same, but the ablation efficiency of the combined pulse on the target decreases seriously. During this period, the maximum electron temperature of the aluminum plasma remains stable. In addition, the combined pulse time delay should be less than 100ns. This study can provide a theoretical reference for combined pulsed laser-induced breakdown plasma spectral enhancement technology.