Dynamics of single-mode rippled shock in laser-irradiated targets using streaked optical pyrometry*

The behavior of non-uniform shocks and interfaces, generated by modulated laser irradiation or surface perturbations, is crucial for understanding systems ranging from inertial confinement fusion to laboratory astrophysics and material properties at high-energy-density conditions. This study investigates the evolution of a single-mode rippled shock in a polystyrene-fused silica sample using streaked optical pyrometry (SOP). Experiments utilize OMEGA-EP laser beams to drive a multimegabar (>3 Mbar) shock into the sample with a preimposed single-mode interface perturbation. Pyrometry measurements of time-resolved thermal emission from the shock front reveal the transfer of single-mode perturbation to the incident shock and its subsequent damped oscillation as the rippled shock traverses fused silica. We describe an analysis framework for interpreting rippled-shock pyrometry data, correlating spectral radiance measurements with rippled-shock velocities. By integrating these velocities, we reconstruct the shock front amplitude evolution, demonstrating an oscillatory decay. We also compare the experimental data with synthetic pyrometry images generated from FLASH hydrodynamic simulations.