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28Complex Systems of Charged Particles and their Interactions with Electromagnetic Radiation 2019
MODELING THE INTERACTION OF AN ULTRA-HIGH INTENSITY LASER PULSE WITH NANOSTRUCTURED TARGETS
Olimpia Budriga1, Emmanuel d'Humieres2, Laura Ionel1, Maria Martis1, Mihai Carabas3
1 National Institute for Laser, Plasma and Radiation Physics, Magurele, Romania, e-mail:
[email protected] 2Universite de Bordeaux - CNRS - CEA, CELIA, Talence, France, e-mail: [email protected] 3University POLITEHNICA of Bucharest, Bucharest, Romania, e-mail: [email protected]
ELI-NP two ten PW lasers will be operational at the end of 2019. Experiments of laser-ion acceleration are envisioned at ELI-NP [1].
This talk presents the results of a numerical study of the interaction of an ultra-high intensity laser pulse with plastic nanostructured foils and flat-top cone targets. The interaction of an ultra-high intensity laser pulse with a flat-top cone target was studied before for a 1 PW laser [2]. 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 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 [3]. We calculated the maximum energy of protons and carbon 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 one GeV and ion energies in the range of ten GeV. The energy of the accelerated protons and carbon ions depends on the dimension of the nanospheres diameter. The maximum proton energies are a little higher for the nanostructured foil targets than for the nanostructured flat-top cone targets. The angular divergencesare similar for both types of targets.
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 [4]. This method aims to provide a complementary approach to the PIC simulations in order to isolate the geometriceffects affecting the incoming laser-plasma interaction.
We can conclude that in the range of parameters studied the nanostructured targets are better than the simple foil and flat-top cone targets to be used for laser-ion acceleration experiments.
References
[1] K. A. Tanaka 2018 Nuclear Photonics Conference p~45// http://www.eli-np.ro/nuclearphotonics2018/talks/04.1.K. Tanaka.pdf.
[2] O. Budriga and E. d'Humieres 2017 Laser Part. Beams 35 (3) 458.
[3] Y. Sentoku and A. Kemp 2008 Journal of Computational Physics 227 (14) 6846.
[4] L. Ionel and D. Ursescu 2016 Opt. Express 24 (7) 7046.\
1 ■ 1 ■ 1 ■ 1 ■ 1 1 1 1 ' I 1 1 _
• lilU'.tl | Kllill t/all ¡Oil * circular polarization
1 A . à * A A
i i 1000 I g *
1 7541 8 S 500 * « * ♦ "■«■111 • * • I.I.I • ■ 1
0 10 30 30 -to 50 60 70 Nanospheres diameter mini 80
Fig. 1. Maximum proton energy versus nanosphere diameter for a plastic foil target.
