A5055673691- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Laser Design and Applications
- Atomic and Molecular Physics
- Magnetic confinement fusion research
- Combustion and Detonation Processes
- Advanced Fiber Laser Technologies
- Particle Dynamics in Fluid Flows
- Particle Accelerators and Free-Electron Lasers
- Laser Material Processing Techniques
- Sports Dynamics and Biomechanics
- Semiconductor Lasers and Optical Devices
- Optical Network Technologies
- Advanced Photonic Communication Systems
- Nuclear Physics and Applications
- Advanced Optical Sensing Technologies
- Cavitation Phenomena in Pumps
- Full-Duplex Wireless Communications
- Radio Frequency Integrated Circuit Design
- Quantum Information and Cryptography
- Electromagnetic Compatibility and Measurements
- Adaptive optics and wavefront sensing
- Solid State Laser Technologies
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2010-2024
CEA DAM Île-de-France
2010-2024
Experiments have been performed evidencing significant stimulated Raman sidescattering (SRS) at large angles from the density gradient. This was achieved in long scale-length high-temperature plasmas which two beams couple to same scattered electromagnetic wave further demonstrating for first time this multiple-beam collective SRS interaction. The nature of coupling and amplification gradient increase global losses produce light novel directions out planes incidence beams. These findings...
The first indirect drive Inertial Confinement Fusion (ICF) experiments on the Laser Megajoule facility were carried out with approximately 150 kJ of laser energy distributed 48 beams (12 quads) arranged in two cones. target consisted a gold vacuum rugby-shaped hohlraum and plastic capsule located at its center, filled deuterium gas fuel. arrangement 12 quads is such that irradiation wall generated three-dimensional (3D) x-ray flux around creating 3D deformations imploding shell. This...
Gas-filled rugby-shaped hohlraums have demonstrated high performances compared to a classical similar diameter cylinder hohlraum with nearly 40% increase of x-ray drive, 10% higher measured peak drive temperature, and an in neutron production. Experimental comparisons been done between rugby, cylinder, elliptical hohlraums. The impact these geometry differences on the laser plasma instabilities is examined. Using hydrodynamic simulations carried out code FCI2 postprocessed by Piranah, we...
The indirect-drive scheme to inertial confinement fusion uses a large number of laser beams arranged in symmetric angular distribution. Collective plasma instabilities can therefore develop that couple all the incident waves located cone daughter wave growing along symmetry axis [D. F. DuBois et al., Phys. Fluids B 4, 241 (1992)]. With complementary diagnostics Thomson scattering and scattered light, we demonstrate occurrence collective stimulated Brillouin sidescattering driving acoustic...
Abstract Short pulse laser plasma interaction experiments using diffraction limited beams provide an excellent platform to investigate the fundamental physics of stimulated Raman scattering. Detailed understanding these instabilities impacts current inertial confinement fusion ignition designs and could potentially impact fast when higher energy lasers are used with longer durations (>1 kJ >1 ps). Using short pulses, can be modeled over entire time particle-in-cell codes validate our...
This Letter reports new experimental results that evidence the transition between absolute and convective growth of stimulated Raman scattering (SRS). Significant reflectivities were observed only when instability grows in regime. In this case, saturation processes efficiently limit SRS reflectivity is shown to scale linearly with laser intensity, electron density temperature. Such a scaling agrees one established by T. Kolber et al. [Phys. Fluids B 5, 138 (1993)10.1063/1.860861] Bezzerides...
We have designed experiments to study the effect of laser wavelength (0.527 versus 0.351 μm) on coupling efficiency in plasma conditions relevant compression and shock ignition (SI) schemes different intensity regimes. A difficult issue was produce interaction that are equivalent for two wavelengths. This obtained by using preformed from a solid target with plasma-preforming beam at same as beam. produced an almost exponential density profile vacuum critical which all mechanisms taken into...
Equivalent stimulated Brillouin backscattering (SBS) saturation levels have been measured in the interaction with 0.527 and $0.351\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ laser beams demonstrating that initial wavelength is not influencing final levels. Experiments performed at two wavelengths similar conditions obtained by preforming plasma from a solid target creation beam converted same as beam. This produces an almost exponential density profile vacuum to critical of which large SBS...
This paper presents an analysis of laser–plasma interaction risks the shock ignition (SI) scheme and experimental results under conditions relevant to corona a compressed target. Experiments are performed on LIL facility at 10 kJ level, LULI 2000 with two beams level 6-beam 100 J in each beam. Different aspects SI pulse studied exploiting either flexibility produce very high intensity or energy long hot plasmas. A continuity is found allowing us draw some conclusions regarding coupling...
The direct and indirect drive schemes for inertial confinement fusion (ICF) make use of a large number laser beams arranged in symmetric angular distribution. preferential decay geometry the three waves resonant couplings, mainly responsible backscattered light single beam experiments, may then be deeply modified region crossing where collective plasma instabilities could develop. Such can occur having common symmetry axis along which they daughter wave. coupling results an increase growth...
A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling minimal backscatter can be achieved in rugby geometry, leading to significantly enhanced implosion performance. nearly 50% increase x-ray drive is associated with earlier bangtime neutron production. The observed enhancement from geometry this study almost twice stronger than previously published results.
CEA implemented an absolutely calibrated broadband soft X-ray spectrometer called DMX on the Omega laser facility at Laboratory for Laser Energetics (LLE) in 1999 to measure radiant power and spectral distribution of radiation Au plasma. The is composed 20 channels covering range from 50 eV keV. energies below 1.5 keV combine a mirror filter with coaxial photo-emissive detector. For above 5 photoemissive detector replaced by conductive intermediate energy (1.5 < photon keV) use only A...
We present in this article direct-drive experiments that were carried out on the Omega facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. Two different pulse shapes tested order to vary implosion stability of same target whose parameters, dimensions and composition, remained same. The configuration allows accurate time-resolved measurement scattered light. show that, provided laser coupling is well controlled, time history, assessed by “bang-time” shell trajectory measurements,...
The Ligne d'Integration Laser (LIL) facility has been designed as a prototype for the MegaJoule (LMJ) which is cornerstone of French 'Simulation Program'. This laser intensively used to test and improve LMJ components. In addition, large panel plasma diagnostics installed currently perform laser–plasma experiments. After brief discussion about LIL design, we present last results in various physics domains.
Backward stimulated Raman and Brillouin scattering (SRS SBS) are experimentally investigated by using two successive 1-μm, 1.5-ps FWHM laser pulses. The collinear pulses, separated 3 or 6 ps of moderate intensities (∼2×10^{16}Wcm^{-2}), fired into a preionized He plasma density ∼2.5-6×10^{19}cm^{-3}. electron waves ion acoustic waves, respectively driven SRS SBS, analyzed through space- time-resolved Thomson scattering. Depending on the parameters, we observe effect first pulse SBS signals...
Proton radiography experiments of laser-irradiated hohlraums performed at the OMEGA laser facility are analyzed using three-dimensional (3D) hydrodynamic simulations coupled to a proton trajectography package. Experiments with three different irradiation patterns were performed, and each produced distinct image. By comparing these results synthetic images obtained by sending protons through plasma profiles in hohlraum from 3D radiation simulations, it is found that simulated agree favorably...
This paper presents experimental results obtained at LULI 2000 and LIL about (i) the compared laser plasma coupling 526 (2ω) 351 nm (3ω) (ii) early imprint suppression using foam targets as smoother of beam. Both experiments are described, part presented discussed.
The effectiveness of a dome-shaped wall covered by thin gold foil (hollow wall) [M. Vandenboomgaerde et al., Phys. Plasmas 25, 012713 (2018)] in holding back the high-$Z$ plasma expansion gas-filled hohlraum is demonstrated for first time experiments reproducing irradiation conditions indirect drive at ignition scale. setup exploits 1D geometry enabling record complete history 8 ns imaging its emission multiple x-ray energy ranges featuring either absorption zones or thermal regions....
This paper presents results obtained in an experiment performed at the LULI 2000 laser facility where we measured saturated Stimulated Raman Scattering (SRS) a supersonic gas jet of ethylene (C2H4). Our conditions correspond to following parameters: kEPWλD = (0.2-0.3), Te (0-1) keV and ne (1.2-10) % critical density 526 nm. The was smoothed with random phase plate had maximal average intensity 1.2x10 15 W/cm² focal spot.
With the arrival of megajoule class laser facilities, features laser-produced plasmas are evolving toward unprecedented high electron temperatures reached in environment a cm-scale indirect-drive Hohlraum for few tens nanoseconds. In this context, need situ experimental characterization plasma parameters becomes critical order to test hydrodynamics simulations these novel conditions. Taking advantage progress achieved last 40 years, Thomson scattering has become classic diagnostic produced...
The CEA/DAM ICF experimental program is currently conducted on LIL and Omega with the goal of improving our simulation tool, FCI2 code. In this effort, we focus typical observables: hohlraum radiation drive history, capsule core shape neutron emission hydrodynamic instability growth. addition to integrated experiment, specific designs are also helpful pinpoint a particular phenomenon. article, review current efforts status, future projects LMJ.
Two x-ray spectrometers have been built for spectroscopy of laser-produced plasmas on OMEGA at the Laboratory Laser Energetics (LLE) by Commissariat à l'Energie Atomique et aux énergies alternatives (CEA). The accessible photon energy range is from 1.5 to 20 keV. first spectrometer, called X-ray CEA Crystal Spectrometer with a Charge-Injection Device (XCCS-CID), records three spectra crystals coupled time integrated CID camera. second one, (XCCS) framing camera, resolved and four two frames...