engleski

EFFECTS OF HIGH POWER LASER ABLATION IN THE SEMICONFINED CONFIGURATION: TARGET SURFACE ORGANIZATION INTO SUPERCOMPLEX STRUCTURES

We report on the results of experiments performed on metal targets in the semiconfined configuration in which the target surface is irradiated from above through a transparent quartz plate positioned ~ 300 microns above the surface. Laser ablation by a XeCl excimer laser (  = 248nm,  = 20ns, I = 7 x 107 to 108W/cm2) occurs in a channel-like trap due to the reflection of the upward propagating plasma shock wave which enhances the horizontal plasma expansion and promotes the formation of a plasma slab. Laser irradiation of a metal target, patterned with a series of parallel micron size scratches, causes the formation of a 1D vortex filament lattice. The interaction of individual and collective vortex filaments organized into 1D lattice with point defects gives rise to various complex multiscale wave-vortex structures which capture physical phenomena on a broad spatial scale. These structures establish an inhomogeneous pattern of vortex filament configurations in various domains of the interaction zone, and stay frozen permanently after pulse termination because of ultrafast cooling, thus making possible a posteriori study.

aser ablation; Rayleigh-Taylor instability; coherent fluid structures; vortex fillaments; supercomplex organisation

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