Laser-driven shock wave propagation in low-density foam targets investigated by time-resolved X-ray radiography and hydrodynamic simulations

We investigated laser-driven shock propagation in low-density foams through coordinated experiments and simulations. At the Vulcan laser facility, a nanosecond laser pulse launched a shock from a plastic ablator–titanium pusher assembly into a 0.1 g cm–3 trimethylolpropane triacrylate foam, diagnosed by side-on, time-resolved X-ray radiography using a picosecond Cu backlighter. This enabled direct tracking of the pusher motion and the shock front. Comparison with one-dimensional and two-dimensional hydrodynamic simulations (MULTI and FLASH) shows good agreement when assuming an effective on-target intensity of (3–5) × 1013 W cm–2, lower than nominal laser estimates, underscoring the influence of coupling losses. An analytical model based on impedance-matched shock relations connects the ablation pressure, pusher dynamics and transmitted shock strength. Overall, the combined results indicate that the foam behaves as an effectively homogeneous medium under these conditions, supporting modelling assumptions for foam-based fusion targets and establishing a validated platform for future shock-propagation studies in low-density materials.