Observation of hydrodynamic effects in laser-irradiated multifoil targets

To experimentally model laser-plasma interaction in low-density porous media, we have started irradiating plastic multifoil targets with a single 1.054 μm laser beam at approximately 1014 W/cm2 at the "Mishen" facility. A first foil directly irradiated was thin enough to burn through and rapidly become underdense. Acceleration and expansion of the high-temperature plasma inward the target, its stagnation under impacts on successive foils, and reverse shock propagation into the plasma corona occur during the laser pulse. Hydrodynamics of plasma in multifoil targets was studied by analyzing the spectral shifts of backscattered laser light and its harmonics. The experimental data interpretation employs results of the one-dimensional hydrodynamic simulation.