Shock dynamics and shock collision in foam layered targets

Abstract

We present an experimental study of the dynamics of shocks generated by the interaction of a double-spot laser in different kinds of targets: simple aluminum foils and foam–aluminum layered targets. The experiment was performed using the Prague PALS iodine laser working at 0.44 μm wavelength and irradiance of a few 1015 W/cm2. Shock breakouts for pure Al and for foam-Al targets have been recorded using time-resolved self-emission diagnostics. Experimental results have been compared with numerical simulations. The shocks originating from two spots move forward and expand radially in the targets, finally colliding in the intermediate region and producing a very strong increase in pressure. This is particularly clear for the case of foam layered targets, where we also observed a delay of shock breakout and a spatial redistribution of the pressure. The influence of the foam layer doped with high-Z (Au) nanoparticles on the shock dynamics was also studied.

Wavelength encoded single-shot high-spatiotemporal resolution all-optical probe

“…电离过程 [27] . 高帧率和高帧数应用场景的探针光 具有高时间分辨率、帧数和帧率的优点, 可用于捕 捉皮秒时间尺度的超快动力学过程, 例如捕捉飞秒 激光诱导的结构等离子体的膨胀演化过程 [28] . 大 时间窗口应用场景的探针光具有高时间分辨率、高 帧数、时间窗口大的优点, 可用于捕捉百皮秒到纳 秒量级的超快动力学过程, 例如捕捉激光和材料相 互作用产生的冲击波的演化 [29] .…”

Explosion and Dynamic Transparency of Low-Density Structured Polymeric Targets Irradiated by a Long-Pulse KrF Laser

“…A direct electron acceleration in self-produced or preliminary drilled capillaries was observed up to a few hundred keV [49], which was associated with a longitudinal component of the electric field in a corrugated waveguide, which retarded the light in phase with electrons [50]. It is expected that the 2D hydrodynamics of low-density foam targets for a 100 ns laser pulse would be rather different from the case of 1D geometry typical for the most laser-foam interaction studies [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] carried out with ns-scale laser pulses. In addition, most plastic materials have a steep rise in absorbance around the KrF laser wavelength [48], which should decrease the plasma formation time for foams.…”

“…Laser-foam interaction, including the ionization dynamics of foams, have been studied experimentally and theoretically in many works, mostly with Nd: glass lasers at a wavelength of λ = 1060 nm, sometimes at second (2ω) or third (3ω) harmonics (see, for example, [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]). It is commonly assumed that foams are initially transparent for laser radiation and that plasma originates from the evaporation and ionization of pore septa.…”