Laser absorption and energy transfer in foams of various pore structures and chemical compositions

Interaction of sub-nanosecond intense laser pulses with foams containing fine and large pores has been studied experimentally. Laser penetration and energy transport in the foam material are measured via streaked side-on x-ray slit images. Shock wave transition through the foam is detected via streaked optical self-emission from foil attached on the foam rear side. The shock transition time increases with the pore size, foam density, and also with the contents of high Z additions in plastic foams. Foil acceleration is observed via 3-frame interferometry. Comparison of experimental results with numerical simulations and an analytical model is underway.