arXiv subjects

E. D'Humières

Publications and source records attributed to E. D'Humières.

3 recordsLinked to original sources

arXiv2026

Investigation of Laser Plasma Instabilities driven by Coupled High-Power Laser Beams in Magnetized Underdense Plasmas

Stimulated Brillouin and Raman scattering (SBS and SRS) are instabilities that affect the propagation of high-power lasers in plasmas. The latter is further affected by Cross-Talk (CT) effects when multiple laser beams are simultaneously propagated in the plasma, as found in the schemes proposed for inertial confinement fusion (ICF). Here we develop a new theoretical model that allows us to evaluate the impact of CT on SBS and SRS in low-density plasmas. As supported by experiments, we demonstrate that CT can lead to a reduction of both SBS and SRS, due to the destabilization of the individually triggered instabilities. We further demonstrate that this destabilization effect is accelerated by applying an externally magnetic field to the plasma, which is also beneficial for the hydrodynamics or fuel heating of ICF. By shedding new light on the promising scheme of magnetized ICF, our findings thus offer beneficial prospects for ICF.

physics.plasm-ph↗

arXiv2018

Synchrotron emission from nanowire-array targets irradiated by ultraintense laser pulses

We present a numerical study, based on two-dimensional particle-in-cell simulations, of the synchrotron emission induced during the interaction of femtosecond laser pulses of intensities $I=10^{21}-10^{23}\,\mathrm{Wcm}^{-2}$ with nanowire arrays. Through an extensive parametric scan on the target parameters, we identify and characterize several dominant radiation mechanisms, mainly depending on the transparency or opacity of the plasma produced by the wire expansion. At $I=10^{22}\,\mathrm{Wcm}^{-2}$, the emission of high-energy ($>10\,\mathrm{keV}$) photons attains a maximum conversion efficiency of $\sim 10\%$ for $36-50\,\mathrm{nm}$ wire widths and $1\,μ\mathrm{m}$ interspacing. This maximum radiation yield is similar to that achieved in uniform plasma of same average (sub-solid) density, but nanowire arrays provide efficient radiation sources over a broader parameter range. We examine the variations of the photon spectra with the laser intensity and the wire material. Finally, we demonstrate that the radiation efficiency can be further enhanced by adding a plasma mirror at the backside of the nanowire array.

physics.plasm-ph↗

arXiv2015

Pair creation in collision of $γ$--ray beams produced with high intensity lasers

Direct production of electron--positron pairs in two photon collisions, the Breit--Wheeler process, is one of the basic processes in the Universe. However, it has never been observed in laboratory because of absence of the intense gamma-ray sources. Laser induced synchrotron sources emission may open for the first time a way to observe this process. A feasibility of an experimental set--up using a MeV photon source is studied in this paper. We compare several $γ$--ray sources, estimate the expected number of electron--positron pairs and competing processes by using numerical simulations including quantum electrodynamic effects.

physics.ins-det↗