401 / 2019-02-28 18:31:27

Modeling the interaction of an ultra-high intensity laser pulse with nanostructured targets

Laser-ion acceleration; Ultra-high intensity pulse; Nanostructured targets

全体主题 > Fundamental Physics at Extremes

ELI-NP two ten PW lasers will be operational at the end of 2019. Experiments of laser-ion acceleration are envisioned at ELI-NP.
This talk presents the results of a numerical study of the interaction of an ultra-high intensity laser pulse with nanostructured foils and flat-top cone targets. The ultra-high intensity laser pulse linearly polarized has the parameters of the two lasers of 10 PW from ELI-NP. The ultra-high intensity laser pulse circularly polarized has the intensity double than in the case of the linear polarization. The foil thickness and the nanospheres diameters are of the order of tens of nanometers. We consider plastic and aluminium targets. We find the optimal geometric dimensions of the targets to obtain almost monoenergetic beams of accelerated ions with low angular divergence.
We performed Particle-in-Cell (PIC) simulations using the two dimensional version of the PIC code PICLS. We calculated the maximum energy of protons, carbon and aluminium ions, the total and localized proton energy spectra, divergence angle, phase space, and the electric field distribution. We obtained proton energies in the range of GeV and ion energies in the range of hundreds of tens of MeV/nucleon. The energy of the accelerated protons depends on the dimension of the nanospheres diameter. Also, a spatio-temporal analysis of the electromagnetic field distribution during the interaction of the high-intensity laser pulses with nanostructured targets has been performed using a commercial software (RSoft, by Synopsys Optical Solution Group). This study is based on finite-difference time-domain (FDTD) method for solving Maxwell equations. This method aims to provide a complementary approach to the PIC simulations in order to isolate the geometric effects affecting the incoming laser-plasma interaction. The maximum proton energies are a little higher for the nanostructured foil targets than for the nanostructured flat-top cone targets. The angular divergences are similar for both types of targets. We can conclude also that the nanostructured targets are better than the simple foil and flat-top cone targets to be used for laser-ion acceleration experiments.