Coarse-Grained Modeling of Radiation Processes in Non-Equilibrium Laser-Induced Plasma

Laser-induced breakdown of gases produces a highly nonequilibrium plasma, the dynamics of which are strongly influenced by radiative transport with the surrounding medium. The absorption spectrum in such flows exhibits extreme multiscale structure, and multiple radiating species contributing overlapping line forests, making high-fidelity radiation–hydrodynamics coupling computationally prohibitive. The present work investigates reduced-order radiation modeling strategies rooted in homogenization-based opacity reduction. The flow and radiation fields generated by Laser-induced breakdown in quiescent molecular oxygen are computed to characterize the structure of the resulting spectrum. Young-measure-based homogenization is implemented to obtain effective opacities and is evaluated on physically plausible emission spectra constructed from Lorentzian line profiles. Though preliminary, the results demonstrate the potential of homogenization techniques in representing the effects of dense line microstructure in Laser-induced breakdown plasmas at significantly reduced cost.