Picosecond Time-Resolved X-Ray Absorption Spectroscopy of Ultrafast Aluminum Plasmas

Abstract

We have used point-projection K-shell absorption spectroscopy to infer the ionization and recombination dynamics of transient aluminum plasmas. Two femtosecond beams of the 100 TW laser at the LULI facility were used to produce an aluminum plasma on a thin aluminum foil (83 or 50 nm), and a picosecond x-ray backlighter source. The short-pulse backlighter probed the aluminum plasma at different times by adjusting the delay between the two femtosecond driving beams. Absorption x-ray spectra at early times are characteristic of a dense and rather homogeneous plasma. Collisional-radiative atomic physics coupled with hydrodynamic simulations reproduce fairly well the measured average ionization as a function of time.

Experimental Characterization of a Strongly Coupled Solid Density Plasma Generated in a Short‐pulse Laser Target Interaction

“…On the other hand, the benchmarking of theoretical models has been mostly limited to comparisons with numerical simulations due to the experimental difficulties in creating strongly coupled plasma conditions in a controlled laboratory environment. Recently, attempts have been made to create strongly coupled plasmas in the laboratory: for example, using sub-picosecond laser pulse irradiation of very thin aluminum foils in order to investigate recombination dynamics in highly transient plasmas [4]. Eidmann et al [5] have also presented a spectroscopical characterization of a solid density strongly coupled Al plasma inferred from He-like and Li-like satellites.…”

More power to X‐rays: New developments in X‐ray spectroscopy

“…Emission spectra from highly ionized Ar ions near 4 keV were recorded. Auderbert et al developed a method with which they used to probe high-temperature plasmas generated with high-energy picosecond laser pulses [147,148]. Recently, Shan et al performed hard X-ray imaging of laserablated materials in a high-pressure background gas using laser-plasma X-ray pulses [149].…”

Source X-UV pour la spectroscopie d'absorption en régime femtoseconde

“…Dans cette expérience, le changement d'intensité d'une raie d'absorption résonnante a été mesurée en fonction du retard séparant la pompe (400 fs à 0.53 m) de la sonde (rayonnement X de 1 ps à 2,5 keV). Plus récemment, les sources de rayonnement X produit par interaction laser-plasma ont été utilisées pour la spectrocopie d'absorption résolue en temps d'un plasma d'Al [12,13], la photoexcitation d'un échantillon de silicium [14] et du XANES (X-ray absorption near edge spectroscopy) résolue en temps d'une solution d'ion Fe(CN) 4 6 dans un solvant [15]. Cependant, dans ces expériences, la résolution temporelle est limitée par la durée du rayonnement X, une caméra CCD étant utilisé pour la mesure.…”