Rapid extraction of laser plasma parameters from Thomson scattering spectrum features

Real-time diagnosis of plasma parameters during the evolution of laser-produced plasma (LPP) is critical for investigating radiation mechanisms and kinetic evolution processes. However, conventional Thomson scattering (TS) diagnostics, which rely on laborious spectral fitting, fail to meet the requirements of real-time applications. This paper proposes a rapid diagnostic method for LPP based on TS spectral pattern matching. By leveraging the direct mapping between the spectral peak shift and Full Width at Half Maximum (FWHM) of the TS electron scattering spectrum, and the corresponding electron temperature and density, a Python-based visual diagnostic system was developed to automate the entire diagnostic workflow. Through the construction of an integrated TS experimental platform, spatiotemporally resolved TS measurements of air plasma were successfully conducted under the experimental conditions of 50 mJ pulse energy and 510 μm focused spot diameter for the ablation laser, and 23 mJ pulse energy and 460 μm focused spot diameter for the probe laser. The diagnostic results reveal that the electron temperature of air plasma decreases from 73200 K to 14000 K, while the electron density decays from 6.12×1017 cm-3 to 7.8×1016 cm-3 with both parameters following a power-law decay. This method effectively eliminates the uncertainties inherent in traditional spectral fitting and substantially reduces diagnostic latency. It provides key technical support for the analysis of LPP spatiotemporal evolution mechanisms and lays a solid experimental and technical foundation for in-situ real-time monitoring and remote online applications.