A5088457767- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Laser-Matter Interactions and Applications
- Laser Design and Applications
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Ion-surface interactions and analysis
- Magnetic confinement fusion research
- Advanced X-ray Imaging Techniques
- Dust and Plasma Wave Phenomena
- Space Satellite Systems and Control
- Random lasers and scattering media
- Advanced Fiber Laser Technologies
- Ocular and Laser Science Research
- Diamond and Carbon-based Materials Research
- Photocathodes and Microchannel Plates
- Laser Material Processing Techniques
- Cold Atom Physics and Bose-Einstein Condensates
- Pulsed Power Technology Applications
- Electron and X-Ray Spectroscopy Techniques
- Plasma Diagnostics and Applications
- Mass Spectrometry Techniques and Applications
- Quantum optics and atomic interactions
- Silicon and Solar Cell Technologies
Centre National de la Recherche Scientifique
2012-2025
Sorbonne Université
2009-2025
Laboratoire pour l'utilisation des lasers intenses
2014-2025
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2012-2025
École Polytechnique
2013-2025
CEA Paris-Saclay
2009-2018
Université Paris-Saclay
2016-2018
Université Paris Cité
2016-2017
Marie Curie
2015
General Atomics (United States)
2014
Electron transport within solid targets, irradiated by a high-intensity short-pulse laser, has been measured imaging K(alpha) radiation from high- Z layers (Cu, Ti) buried in low- (CH, Al) foils. Although the laser spot is approximately 10 microm [full width at half maximum (FWHM)], electron beam spreads to > or =70 FWHM <20 of penetration into an Al target then, depths >100 microm, diverges with 40 degree spreading angle. Monte Carlo and analytic models are compared our data. We find that...
The acceleration of electrons injected in a plasma wave generated by the laser wakefield mechanism has been observed. A maximum energy gain 1.6 MeV measured and longitudinal electric field is estimated to 1.5 GV/m. experimental data agree with theoretical predictions when 3D effects are taken into account. duration inferred from number accelerated order 1 ps.
The paper presents theoretical analysis and experimental results concerning the major physical issues in shock-ignition approach. These are following: generation of a high amplitude shock imploding target, laser–plasma interaction physics under conditions laser intensities needed for excitation, symmetry stability propagation, role fast electrons symmetrization pressure fuel preheat. models numerical simulations compared with specially designed experiments on plasma excitation plane...
We report on rear-side optical self-emission results from ultraintense laser pulse interactions with solid targets. A prompt emission associated a narrow electron jet has been observed up to aluminum target thicknesses of 400 microm typical spreading half-angle 17 degrees. The quantitative the emitted energy are consistent models where is due transition radiation electrons reaching back surface or synchrotron-type pulled target. These transport simulation give an indication temperature few...
We report on shadowgraphic measurements showing the first space- and time-resolved snapshots of ultraintense laser pulse-generated fast electrons propagating through a solid target. A remarkable result is formation highly collimated jets ( $<20\ensuremath{-}\ensuremath{\mu}\mathrm{m}$) traveling at velocity light extending up to 1 mm. This feature clearly indicates magnetically assisted regime electron transport, critical interest for ignitor scheme. Along with these jets, we detect...
The formation and evolution of density channels created by the interaction a short bright (600 fs, $5\ifmmode\times\else\texttimes\fi{}{10}^{18}\mathrm{W}{\mathrm{cm}}^{\ensuremath{-}2}\ensuremath{\mu}{\mathrm{m}}^{2}$) laser pulse with preformed plasma are studied means experiments 2D particle-in-cell (PIC) simulations. Hollow observed interferometry, fast radial expansion $(5\ifmmode\times\else\texttimes\fi{}{10}^{8}\mathrm{cm}/\mathrm{s})$ is measured. Magnetic fields around 50 MG...
Fast electron generation and propagation were studied in the interaction of a green laser with solids. The experiment, carried out LULI TW (350 fs, 15 J), used K(alpha) emission from buried fluorescent layers to measure transport. Results for conductors (Al) insulators (plastic) are compared simulations: plastic, inhibition fast electrons is observed, due electric fields which become dominant factor
The second harmonic of the laser light (2omega(0)) is observed on rear side thick solid targets irradiated by a beam at relativistic intensities. This emission explained acceleration pulse in front target short bunches electrons separated period (or half period) light. When reaching target, these electron emit coherent transition radiation 2omega(0). observations indicate that, our conditions, minimum fraction energy transferred to order 1%.
Relativistic electrons are produced, with energies up to 20 MeV, by the interaction of a high-intensity subpicosecond laser pulse ( $1\ensuremath{\mu}\mathrm{m}$, $300\mathrm{fs}$, ${10}^{19}\mathrm{W}/{\mathrm{cm}}^{2}$) an underdense plasma. Two suprathermal electron populations appear temperatures 1 and 3 MeV. In same conditions, beam transmission is increased 20%--30%. We observe both features along evidence channeling. A fluid model predicts strong self-focusing pulse. Acceleration in...
We present experimental and numerical results on the propagation energy deposition of laser-generated fast electrons into conical targets. The first part reports measurements performed in various configurations order to assess predicted benefit targets over standard planar ones. For conditions investigated here, electron-induced heating is found be much weaker cone-guided irradiated at a laser wavelength 1.057μm, whereas frequency doubling pulse permits us bridge disparity between This...
We provide a review of selected experiments on fast electron transport in solids and plasmas following laser-matter interaction at relativistic intensities. Particular attention is given to precise measurements intense laser pulses, energy transfer the mean kinetic electrons. discuss detail mechanism loss solid warm dense targets. show that stopping due resistive electric field collimation magnetic play significant roles dynamics. It has also been shown reducing size target can significantly...
We present experimental results on fast-electron energy deposition into solid targets in ultrahigh intensity laser-matter interaction. X-ray K alpha emission spectroscopy with absolute photon counting served to diagnose propagation multilayered targets. Target heating was measured from ionization-shifted emission. Data show a 200 microm range Al. The relative intensities of spectrally shifted Al lines imply mean temperature few tens eV up 100 depth. Experimental suggest refluxing the...
Thin, mass-limited targets composed of $\mathrm{V}/\mathrm{Cu}/\mathrm{Al}$ layers with diameters ranging from 50 to $300\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ have been isochorically heated by a 300 fs laser pulse delivering up 10 J at $2\ifmmode\times\else\texttimes\fi{}{10}^{19}\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$ irradiance. Detailed spectral analysis the Cu x-ray emission indicates that highest temperatures, order 100 eV, reached when irradiating smallest high-contrast,...
Fast electrons produced by a 10 ps, 160 J laser pulse through laser-compressed plastic cylinders are studied experimentally and numerically in the context of fast ignition. K(α)-emission images reveal collimated or scattered electron beam depending on initial density compression timing. A numerical transport model shows that implosion-driven electrical resistivity gradients induce strong magnetic fields able to guide electrons. The good agreement with measured sizes provides first...
This paper describes the first experimental demonstration of guiding a relativistic electron beam in solid target using two co-linear, relativistically intense, picosecond laser pulses. The pulse creates magnetic field which guides higher current fast generated by second pulse. effects intensity ratio, delay, total energy and intrinsic pre-pulse are examined. Thermal K{\alpha} imaging showed reduced emission size, increased peak at delays 4 - 6 ps, an ratio 10 : 1 (second:first) 186 J. In...
Transmission of a subpicosecond relativistic laser pulse is observed through solid foils and preformed overcritical plasmas. rates near 10% for densities above $10\ifmmode\times\else\texttimes\fi{}{n}_{c}$ are measured. A moderately strong threshold in intensity found order to observe this effect. The experimental results as well preliminary particle-in-cell simulations suggest that thin the transmission explicable by rapid heating expansion transmissive conditions during pulse. Self-induced...
Harmonics of the laser light have been observed from rear side solid targets irradiated by a beam at relativistic intensities. This emission evidences acceleration subfemtosecond electron bunches pulse in front target. These emit coherent transition radiation (CTR) when passing through back surface The spectral features signal recorded for thicknesses up to several hundred microns are consistent with electrons being accelerated both electric field—via vacuum heating and/or resonance...
The capacity to launch a strong shock wave in compressed target the presence of large preplasma has been investigated experimentally and numerically planar geometry. experiment was performed on LULI 2000 laser facility using one beam compress second simulating intensity spike ignition scheme. Thanks set diagnostics, it possible compare accurately experimental results with 2D numerical simulations. A good agreement observed even if more detailed study laser-plasma interaction for is necessary...
We present experimental and numerical results on intense-laser-pulse-produced fast electron beams transport through aluminum samples, either solid or compressed heated by laser-induced planar shock propagation. Thanks to absolute K(α) yield measurements its very good agreement with from simulations, we quantify the collisional resistive stopping powers: for current densities of ≈ 8 × 10(10) A/cm(2) they reach 1.5 keV/μm 0.8 keV/μm, respectively. For higher up 10(12)A/cm(2), simulations show...
We describe an experiment performed at the LULI laser facility using advanced radiographic technique that allowed obtaining 2D, spatially resolved images of a shocked buried-code-target. The is suitable for applications on Fast Ignition as well Warm Dense Matter research. In our experiment, it to show cone survival up Mbar pressures and measure shock front velocity fluid associated laser-generated shock. This one point polar porous carbon.
Abstract The ability to produce long-scale length (i.e. millimeter scale-length), homogeneous plasmas is of interest in studying a wide range fundamental plasma processes. We present here validated experimental platform create and diagnose uniform with density close or above the critical density. target consists polyimide tube filled an ultra low-density plastic foam where it was heated by x-rays, produced long pulse laser irradiating copper foil placed at one end tube. temperature ionized...
At the École Polytechnique « LULI » facility, we have measured impulse coupling coefficient Cm (target momentum per joule of incident laser light) with several target materials in vacuum, at 1057 nm and 400 fs 80 ps pulse duration. A total 64 shots were completed a two-week experimental campaign, divided between two durations among materials. Our main purpose was to resolve wide discrepancies reported values for 100 region, where many applications exist. secondary compare The obtained by...
Using space-time-resolved Thomson scattering, we investigate experimentally the development of electrostatic waves in a preformed undercritical helium plasma driven by 1.059 μm laser pulse ∼1.5 ps duration and ∼10^{15-16} W cm^{-2} mean intensity. We observe excitation intense ion (IAWs) over broad wave number range, distinct from what is expected stimulated Brillouin scattering or Langmuir decay instability. These IAWs are correlated with occurrence backward Raman (B-SRS) at earlier times...
Measurements of stimulated Raman scattering (SRS) reflectivity produced by the interaction between a short 450-fs, 1.06-\ensuremath{\mu}m laser pulse and large underdense preformed plasma are presented. Experimental results show that SRS sharply increases as intensity beam approaches 1${0}^{16}$ W/c${\mathrm{m}}^{2}$ from below saturates for intensities greater than 1${0}^{17}$ W/c${\mathrm{m}}^{2}$. These found to be in very good agreement with those initial transient stage theory starting...
Signatures of filamentation have been observed in preformed plasmas using complementary diagnostics: time-resolved images the transmitted laser light, dark field imaging, and spectra Raman light. This last diagnostic clearly shows presence small channels inside plasma with temporal evolution agreement formation filaments. The filamentary structures disappeared when random phase plates were used beam. result is a theoretical analysis showing that does not grow speckle size smaller than...