Numerical Analysis of Collimated and Focused Laser Beam Propagation Across Planar Shockwaves

This work presents a numerical study of laser beam diffraction caused by propagation across a planar shock interface inside a shock tube. By numerically simulating beam propagation, we explore the influence of wavelength, shock speed, beam waist, and alignment. The ideal gas approximation is used to calculate the shock thickness using several approaches. This thickness is then used to calculate the disturbance induced by the shock on the laser beam. The results show how variations in different beam parameters influence the captured response, presented as integrated irradiance. While the shock thickness is calculated assuming an ideal gas and two-body interactions in air, the post-shock chemistry is calculated using the Chemical Equilibrium with Applications (CEA) solver, accounting for real-gas properties. Overall, this model offers a theoretical estimate of the signal behavior expected during beam propagation across a planar shock.