Spectroscopic characterization of an ultrashort-pulse-laser-driven Ar cluster target incorporating both Boltzmann and particle-in-cell models

Abstract

A model that solves simultaneously both the electron and atomic kinetics was used to generate a synthetic He alpha and satellite x-ray spectra to characterize a high intensity ultrashort laser driven Ar cluster target experiment. In particular, level populations were obtained from a detailed collisional-radiative model where collisional rates were computed from a time varying electron distribution function obtained from the solution of the zero-dimensional Boltzmann equation. In addition, a particle-in-cell simulation was used to model the laser interaction with the cluster target and provided the initial electron energy distribution function (EEDF) for the Boltzmann solver. This study suggests that a high density average, <Na>high, of 3.2 x 10(20) cm(-3) was held by the system for a time, delta tau, of 5.7 ps, and during this time the plasma was in a highly nonequilibrium state in both the EEDF and the ion level populations.

Dynamics of rare gas nanoclusters irradiated by short and intense laser pulses

“…The spectrum exhibits intense emission lines associated to very high Ar qþ charged states with 13 q 16 and supports previous time-integrated measurements [13,20,21]. The appearance of such highly charged states clearly indicates the importance of electroneion collisions in the laserecluster dynamics as lasereAr atom collisions can only lead to Ar 8þ formation under identical irradiation conditions.…”

“…Therefore, our second aim is to design an experiment to provide detailed information about the dynamics of the laserecluster interaction. Thus we aspired to obtain a time-dependent picture of the dynamics, beyond previous time-integrated X-ray measurements [13,21]. Accordingly, we have coupled a streak camera to a conical crystal to yield energy-and time-resolved X-ray spectra, in the keV range and on picosecond timescale.…”

Generation of Quantum Beams in Large Clusters Irradiated by Super‐Intense, High – Contrast Femtosecond Laser Pulses

“…We found that the best interaction point of laser beam with cluster beam was vertically about 1 mm above the gas jet and longitudinally about 0.5 mm away from the nozzle center. As it is well-known that the initial size of clusters is crucial point for the level of cluster ionization by fs laser pulse [51,52]. In such case, we first of all provided optimization the size of clusters.…”

Characterization of cluster/monomer ratio in pulsed supersonic gas jets

“…Even at relativistic intensities, it is often assumed that the relative fraction of hot electrons is below 10 −4 [70,71]. This condition guarantees that the hot electrons are unable to change Z c of all the ions significantly on a time scale of picosecond.…”