Laser interactions with plastic foam—metallic foil layered targets

Abstract

Interactions of the laser beam of iodine laser 'PALS' with low-density foam targets and acceleration of Al foils by the pressure of heated foam matter are investigated here, both experimentally and theoretically. An x-ray streak camera was used for the evaluation of the speed of energy transfer through the porous foam material. X-ray streak records show no noticeable emission near the Al foil at the rear side of a 400 µm thick foam and, thus, Al foil is most likely accelerated without significant heating and expansion. Accelerated foil velocities, measured by three-frame optical shadowgraphy, reach up to 10 7 cm s −1 . Experimental results compare well with our two-dimensional hydrodynamics simulations and with an approximate analytical model.

Laser-supported ionization wave in under-dense gases and foams

“…III A, the first two terms are given by Eq. (8). The plasma kinetic energy depends on the properties of the rarefaction wave.…”

“…Subcritical foams can be directly ionized by the laser pulse itself. [6][7][8] The ionization wave in such foams may propagate with a supersonic velocity so the pressure perturbations will not be impressed at the ablator surface. Supersonic propagation of the ionization wave has been demonstrated in the experiment conducted on the Ligne d'Integration Laser (LIL) laser facility.…”

D-D nuclear fusion processes induced in polyethylene foams by TW Laser-generated plasma

“…The use of thick "advanced targets", promoting the laser absorption and the ion acceleration, for example based on porous (foam) polymers, permits to enhance both ion energy and ion yield accelerating protons at energies of the order of some MeVs. Tailored foams, due to their low density (approximately 1-10 mg/cm 3 ) and high porosity, can be employed as thick and thin films covering a substrate in order to enhance the laser illuminated area, to reduce the reflection component of the laser light, to increase the laser penetration in the under-critical produced plasma and to induce self-focusing effect due to the high refraction index in the produced pre-plasma vapor [7].…”

Direct evidence of gas-induced laser beam smoothing in the interaction with thin foils

“…12,13 Alternatively, very low-density ͑undercritical and transparent͒ foams may reduce the imprint acting as dynamic phase plates. 14 Recently a new approach to the problem of smoothing has been proposed, based on the interaction of the laser pulse with a low-density gas jet. In a preliminary experiment 15 a speckled laser beam was sent through a gas jet and imaged both statically ͓with a charge coupled device ͑CCD͔͒ and dynamically ͑with a streak camera͒.…”