Dual-pulse laser-induced breakdown spectroscopy (DP-LIBS) is essential for highly sensitive trace element detection. Although various mechanisms have been proposed for its signal enhancement,fur-ther investigation is needed regarding plasma radiation fluorescence characteristics,spatial distribution of plasma temperature,and particle number density. This study developed a theoretical model based on laser ablation and two-dimensional axisymmetric fluid dynamics to simulate the spatiotemporal evolution of plas-ma generation and irradiance in aluminum-magnesium alloy under single-pulse LIBS and coaxial dual-pulse DP-LIBS conditions. We compared spectral line intensity enhancements at different pulse intervals and an-alyzed the spatial distribution of plasma temperature,particle number densities,and plasma shielding ef-fects to clarify the signal enhancement mechanism of DP-LIBS. Results indicate that the increased particle number density and plasma temperature from the second laser beam primarily drive the enhanced plasma ra-diation signals,while plasma shielding occurs mainly at the target surface boundary layer. This study offers a vital theoretical foundation for experimental research and signal enhancement in DP-LIBS,aiding re-searchers in optimizing experimental device parameters efficiently.
维普
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