84 results on '"BATON, S. D."'
Search Results
2. Recent results at LULI on fast electron transport with and without guiding cone in the context of fast ignitor
- Author
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Baton, S. D., Koenig, M., Fuchs, J., Gremillet, L., Rousseaux, C., Batani, D., Morace, A., Nakatsutsumi, M., Kodama, R., Norimatsu, T., Nishida, A., Dorchies, F., Fourment, C., Santos, J. J., Rassuchine, J., and Cowan, T.
- Published
- 2009
- Full Text
- View/download PDF
3. Two-channel high-resolution quasi-monochromatic X-ray imager for Al and Ti plasma.
- Author
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Do, A., Briat, M., Baton, S. D., Krumrey, M., Lecherbourg, L., Loupias, B., Pérez, F., Renaudin, P., Rubbelynck, C., and Troussel, Ph.
- Subjects
X-rays ,ENERGY density ,SYNCHROTRONS ,LASER pulses ,FRESNEL diffraction - Abstract
High-resolution, high-sensitivity X-ray imaging is a real challenge in high-energy density plasma experiments. We present an improved design of the Fresnel ultra high-resolution imager instrument. Using an Ultra-High-Intensity (UHI) laser to generate hot and dense plasma in a small volume of an Al-Ti mixed target provides simultaneous imaging of both Al and Ti X-ray emission. Specifically, the Al He
β (or Lyβ ) and the Ti Heα lines are imaged with a resolution of (2.7 ± 0.3) μm and (5.5 ± 0.3) μm, respectively. It features two transmission Fresnel phase zone plates fabricated on the same substrate, each associated with a multilayer mirror for spectral selection. Their spatial resolution has been measured on the PTB synchrotron radiation facility laboratory at BESSY II and on the EQUINOX laser facility. Results obtained on an UHI experiment highlight the difference of emission zone sizes between Al and Ti lines and the versatility of this instrument. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
4. Fast electron propagation in high-density plasmas created by 1D shock wave compression: experiments and simulations
- Author
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Santos, J. J., Batani, D., Mckenna, P., Baton, S. D., Dorchies, F., Dubrouil, A., Fourment, C., Hulin, S., Humieres, E. D., Ph Nicolai, Gremillet, L., Debayle, A., Honrubia, J. J., Carpeggiani, P., Veltcheva, M., Quinn, M. N., Brambrink, E., Tikhonchuk, V., Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Laboratoire d'optique appliquée (LOA), École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica 'Giuseppe Occhialini' = Department of Physics 'Giuseppe Occhialini' [Milano-Bicocca], Università degli Studi di Milano-Bicocca [Milano] (UNIMIB), SUPA, Department of Physics (SUPA), University of Strathclyde [Glasgow], Laboratoire pour l'utilisation des lasers intenses (LULI), Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Pôle Fromager AOP du Massif Central, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Universidad Politécnica de Madrid (UPM), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Università degli Studi di Milano-Bicocca = University of Milano-Bicocca (UNIMIB)
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[PHYS]Physics [physics] ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience; no abstract
- Published
- 2010
5. Enhanced Hot Electron Localization and Heating in High-Contrast Ultra-Intense Laser Irradiation of Sharp Micro-Cone Targets
- Author
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Rassuchine, J., DHumières, E., Baton, S. D., Guillou, P., Koenig, M., Fuchs, J., Audebert, P., Kodama, R., Nakatsutsumi, M., Ozaki, N., Batani, D., Morace, A., Redaelli, R., Gremillet, L., Rousseaux, C., Dorchies, F., Fourment, C., Santos, J. J., Adams, J., Korgan, G., Malekos, S., Hansen, S. B., Shepherd, R., Flippo, K., Gaillard, S., Sentoku, Y., and Cowan, T. E.
- Abstract
We report experiments demonstrating enhanced coupling efficiencies employing high contrast laser irradiation of nano-fabricated conical targets. Peak temperatures near 200 eV are observed with modest laser energy (10 J), revealing similarities in hot electron localization and material heating to reduced mass targets. Collisional particle-in-cell simulations attribute this enhancement to self-generated resistive magnetic fields forming within the cone wall, which effectively confine the energetic electrons to heat a reduced volume at the cone tip.
- Published
- 2009
6. Enhanced hot-electron localization and heating in high-contrast ultraintense laser irradiation of microcone targets
- Author
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Rassuchine, J., Humieres, E. D., Baton, S. D., Guillou, P., Koenig, M., Chahid, M., Perez, F., Fuchs, J., patrick Audebert, Kodama, R., Nakatsutsumi, M., Ozaki, N., Batani, D., Morace, A., Redaelli, R., Gremillet, L., Rousseaux, C., Dorchies, F., Fourment, C., Santos, J. J., Adams, J., Korgan, G., Malekos, S., Hansen, S. B., Shepherd, R., Flippo, K., Sentoku, Y., Cowan, T. E., Centre d'Etudes Lasers Intenses et Applications (CELIA), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire pour l'utilisation des lasers intenses (LULI), Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Critical Care Department, Hospital de Sabadell, CIBER Enfermedades Respiratorias, Institut of Applied Physics (IAP), Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Graduate School of Engineering, Osaka University, Graduate School of Engineering, Graduate School of Engineering [Suita, Osaka], Osaka University [Osaka], Dipartimento di Fisica 'Giuseppe Occhialini' = Department of Physics 'Giuseppe Occhialini' [Milano-Bicocca], Università degli Studi di Milano-Bicocca = University of Milano-Bicocca (UNIMIB), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), DAM Île-de-France (DAM/DIF), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'optique appliquée (LOA), École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Osaka University, and Università degli Studi di Milano-Bicocca [Milano] (UNIMIB)
- Subjects
[PHYS]Physics [physics] ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience; no abstract
- Published
- 2009
7. Stimulated backward Raman scattering driven collectively by two picosecond laser pulses in a bi- or multi-speckle configuration.
- Author
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Glize, K., Rousseaux, C., Bénisti, D., Dervieux, V., Gremillet, L., Baton, S. D., and Lancia, L.
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PLASMA density ,LASER pulses ,RAMAN scattering ,ULTRASHORT laser pulses ,PLASMA lasers - Abstract
In this paper, we investigate, both experimentally and numerically, the backward stimulated Raman scattering (SRS) excited collectively by two laser pulses. The experiments have been carried out at the LULI facility using two co-propagating 1-µm wavelength, 1.5-ps duration laser pulses focused in a preformed underdense plasma. A particular emphasis is laid on the configuration where the pulses are focused side-by-side, with a lateral distance of 80-90 µm, but not simultaneously. It is experimentally demonstrated that a weak-intensity speckle, ineffective when fired alone in a preformed plasma, yields a significant SRS-induced reflectivity if launched a few picoseconds after a strong one. The data have been obtained by using both highly space-time resolved Thomson diagnostics and space-resolved SRS reflectivity measurements. By choosing either parallel or orthogonal polarizations for the two laser pulses, our experiments shed light on the role of either electrostatic or electromagnetic seeding in enhancing SRS from weak-intensity speckles. A major finding is that seeding operates over unexpectedly long times (15-20 ps under our experimental conditions). Similar results are obtained in lower-density plasmas, or when the weak pulse is smoothed by a random phase plate, thus leading to multiple speckle interaction, while the strong pulse is focused within the speckle pattern. The data are discussed with the help of particle-in-cell numerical simulations, which confirm the destabilizing effect of the strong pulse over the weak one after a short transient time. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
8. High-resolution quasi-monochromatic X-ray imaging using a Fresnel phase zone plate and a multilayer mirror.
- Author
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Do, A., Troussel, Ph., Baton, S. D., Dervieux, V., Gontier, D., Lecherbourg, L., Loupias, B., Obst, L., Pérez, F., Renaudin, P., Reverdin, Ch., Rubbelynck, C., Stemmler, Ph., and Soullié, G.
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X-ray imaging ,QUASIUNIFORM spaces ,FRESNEL lenses ,ZONE plates ,MULTILAYER mirrors - Abstract
High-resolution, high-sensitivity X-ray imaging is a real challenge in laser plasma diagnostic to attain reliable data in high-energy density plasma experiments. In this context, ultra-high-intensity lasers generate hot and dense plasma but only in a small volume. An experiment has been performed at the LULI2000 laser facility to diagnose such plasma conditions from thermal spectroscopic data. To image the emission zone plasma's Al Heβ, a Fresnel-lens-based X-ray imager has been developed. It features a 846 μm-diameter Fresnel Phase Zone Plate (FPZP) and a Pd/B4C multilayer mirror (thickness d = 5.1 nm). This association can be used between 1500 eV and 2100 eV. The FPZP's efficiency was measured on a synchrotron facility (SOLEIL) and its spatial resolution in a laser facility (EQUINOX). The mirror reflectivity was measured on the synchrotron facility BESSY II. With experimental conditions, the system resolution reaches 3.8 ± 0.6 μm with an adequate efficiency in the 1800 eV-1900 eV energy range with a solid angle of 9 × 10
-6 sr. Consequently, a FPZP is an excellent optics setup for high-resolution quasi-monochromatic X-ray imaging and provides a good collection angle. Bragg-Fresnel lenses, based on the principle of FPZP and mirrors, are currently designed for an X-ray imager at the Laser MégaJoule facility. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
9. Relativistic electron beam transport and characteristics in solid density plasmas
- Author
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Snavely, R. A., Amiranoff, F., Andersen, C., Batani, D., Baton, S. D., Thomas Cowan, Fisch, N., Freeman, R., Gremillet, L., Hall, T., Hatchett, S., Hill, J., Key, M. H., King, J., Koch, J., Koenig, M., Lasinski, B., Langdon, B., Mackinnon, A., Martinolli, E., Norreys, P., Parks, P., Perelli-Cippo, E., Le Gloahec, M. R., Rosenbluth, M., Rousseaux, C., Santos, J. J., Scianitti, F., Tabak, M., Town, R., and Stephens, R.
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Physics::Plasma Physics - Abstract
The transport of intense relativistic electron beams in solid density plasma was analyzed. Ponderomotive kinetics modeling code (MPK) for the average relativistic laser-plasma interaction for laser absorption in under-dense or below critical density plasma was proposed. The focused peak intensity of the Petawatt laser system was measured as high as 3.1020W / cm 2. It was found that there was significant lateral electron transport, but of low energy electrons, into the solid.
- Published
- 2004
10. Study of Non-LTE Spectra Dependence on Target Mass in Short Pulse Laser Experiments.
- Author
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Back, C. A., Audbert, P., Baton, S. D., Bastiani-Ceccotti, S., Guillou, P., Lecherbourg, L., Barbrel, B., Gauci, E., Koenig, M., Gremillet, L., Rousseaux, C., Giraldez, E., and Phommarine, S.
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NONLINEAR optics ,LIGHT sources ,LASER beam scattering ,OPTOELECTRONIC devices ,SPECTRUM analysis - Abstract
Backlight sources created from short pulse lasers are useful probes of high energy density plasmas because of their short duration and brightness. Recent work has shown that the production of Kα radiation can be manipulated by the size and geometry of the targets. Empirical relationships suggest that the electron reflux in the target plays an important role in the heating of these targets to create x-ray backlight sources. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
11. Propagation In Matter Of Currents Of Relativistic Electrons Beyond The Alfven Limit, Produced In Ultra-High-Intensity Short-Pulse Laser-Matter Interactions.
- Author
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Batani, D., Baton, S. D., Manclossi, M., Amiranoff, F., Koenig, M., Santos, J. J., Martinolli, E., Gremillet, L., Popescu, H., Antonicci, A., Rousseaux, C., Rabec Le Gloahec, M., Hall, T., Malka, V., Cowan, T. E., Stephens, R., Key, M., King, J., and Freeman, R.
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LASER beams , *ULTRASHORT laser pulses , *PARTICLES (Nuclear physics) , *PHYSICS , *ELECTRONS , *MAGNETOHYDRODYNAMIC waves - Abstract
This paper reports the results of several experiments performed at the LULI laboratory (Palaiseau, France) concerning the propagation of large relativistic currents in matter from ultra-high-intensity laser pulse interaction with target. We present our results according to the type of diagnostics used in the experiments: 1) Kα emission and Kα imaging, 2) study of target rear side emission in the visible region, 3) time resolved optical shadowgraphy. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
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12. Generation and Transport of Fast Electrons in Laser Irradiated Targets at Relativistic Intensities.
- Author
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Amiranoff, F., Baton, S. D., Gremillet, L., Guilbaud, O., Koenig, M., Martinolli, E., Santos, J. J., Le Gloahec, M. Rabec, Rousseaux, C., Hall, T., Batani, D., Bernardinello, A., Greison, G., Perelli, E., Scianitti, F., Key, M. H., Koch, J. A., Mackinnon, A. J., Freeman, R. R., and Snavely, R.A.
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ULTRASHORT laser pulses , *IRRADIATION , *ELECTRON accelerators - Abstract
The transport of relativistic electrons in solid targets irradiated by a short laser pulse at relativistic intensities has been studied both experimentally and numerically. A Monte-Carlo collision code takes into account individual collisions with the ions and electrons in the target. A 3D-hybrid code takes into account these collisions as well as the generation of electric and magnetic fields and the self-consistent motion of the electrons in these fields. It predicts a magnetic guiding of a fraction of the fast electron current over long distances and a localized heating of the material along the propagation axis. In experiments performed at LULI on the 100 TW laser facility, several diagnostics have been implemented to diagnose the geometry of the fast electron transport and the target heating. The typical conditions were: E[SUBl] ≤ 20 J, &lembda; = 1 μm, τ ≈ 300 fs, I &aysmp; 10[SUP18]-5.10[SUP19]W/cm[SUP2]. The results indicate a modest heating of the target (typically 20-40 eV over 20 μm to 50 μm), consistent with an acceleration of the electrons inside a wide aperture cone along the laser axis. [ABSTRACT FROM AUTHOR]
- Published
- 2002
13. Velocity Interferometer blanking due to preheating in a double pulse planar experiment.
- Author
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Laffite, S., Baton, S. D., Combis, P., Clerouin, J., Koenig, M., Recoules, V., Rousseaux, C., and Videau, L.
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INTERFEROMETERS , *HEATING , *OPTICAL pyrometers , *QUARTZ , *SIGNALS & signaling - Abstract
Optical diagnostics, such as VISAR (Velocity Interferometer System for Any Reflector) or SOP (Streaked Optical Pyrometry), have become essential in shock timing experiments. Their high precision allows for accurate measurements of shock velocities, chronometry, and brightness temperature. However, in some instances, these measurements can be compromised. In planar shock coalescence experiments recently performed at the LULI facility [Baton et al., Phys. Rev. Lett. 108, 195002 (2012)], VISAR signal loss was observed. In these experiments, a strong shock launched by a high-intensity spike catches up with a previously shock launched by an earlier, lowintensity beam. The disappearance of the VISAR signal is attributed to a preheating of the coronal plasma by x-rays generated by the high intensity spike. The signal does not disappear if the highintensity spike starts after VISAR probe beam begins to reflect off of the first shock. The VISAR diagnostic, modeled using an assessment of the optical index in quartz, compares favorably to experimental results. This provides evidence that x-ray preheating can cause blanking of the VISAR signal in quartz. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
14. Unraveling resistive versus collisional contributions to relativistic electron beam stopping power in cold-solid and in warm-dense plasmas.
- Author
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Vauzour, B., Debayle, A., Vaisseau, X., Hulin, S., Schlenvoigt, H. -P., Batani, D., Baton, S. D., Honrubia, J. J., Nicoläı, Ph., Beg, F. N., Benocci, R., Chawla, S., Coury, M., Dorchies, F., Fourment, C., d'Humières, E., Jarrot, L. C., McKenna, P., Rhee, Y. J., and Tikhonchuk, V. T.
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RELATIVISTIC electron beams ,STOPPING power (Nuclear physics) ,PLASMA collision processes ,DENSE plasmas ,ELECTRICAL resistivity ,ELECTRON beams ,ALUMINUM - Abstract
We present results on laser-driven relativistic electron beam propagation through aluminum samples, which are either solid and cold or compressed and heated by laser-induced shock. A full numerical description of fast electron generation and transport is found to reproduce the experimental absolute K
α yield and spot size measurements for varying target thicknesses, and to sequentially quantify the collisional and resistive electron stopping powers. The results demonstrate that both stopping mechanisms are enhanced in compressed Al samples and are attributed to the increase in the medium density and resistivity, respectively. For the achieved time- and space-averaged electronic current density, 〈jh 〉 ~ 8 × 1010 A/cm² in the samples, the collisional and resistive stopping powers in warm and compressed Al are estimated to be 1:5 keV/μm and 0:8 keV/μm, respectively. By contrast, for cold and solid Al, the corresponding estimated values are 1:1 keV/μm and 0:6 keV/μm. Prospective numerical simulations involving higher jh show that the resistive stopping power can reach the same level as the collisional one. In addition to the effects of compression, the effect of the transient behavior of the resistivity of Al during relativistic electron beam transport becomes progressively more dominant, and for a significantly high current density, jh ~ 1012 A/cm², cancels the difference in the electron resistive stopping power (or the total stopping power in units of areal density) between solid and compressed samples. Analytical calculations extend the analysis up to jh = 1014 A/cm² (representative of the full-scale fast ignition scenario of inertial confinement fusion), where a very rapid transition to the Spitzer resistivity regime saturates the resistive stopping power, averaged over the electron beam duration, to values of ~1keV/μm. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
15. Measuring fast electron spectra and laser absorption in relativistic laser-solid interactions using differential bremsstrahlung photon detectors.
- Author
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Scott, R. H. H., Clark, E. L., Pérez, F., Streeter, M. J. V., Davies, J. R., Schlenvoigt, H.-P., Santos, J. J., Hulin, S., Lancaster, K. L., Baton, S. D., Rose, S. J., and Norreys, P. A.
- Subjects
PHOTON detectors ,MONTE Carlo method ,ELECTRON research ,DETECTORS ,MAGNETIC spectrometer - Abstract
A photon detector suitable for the measurement of bremsstrahlung spectra generated in relativistically intense laser-solid interactions is described. The Monte Carlo techniques used to extract the fast electron spectrum and laser energy absorbed into forward-going fast electrons are detailed. A relativistically intense laser-solid experiment using frequency doubled laser light is used to demonstrate the effective operation of the detector. The experimental data were interpreted using the 3-spatial-dimension Monte Carlo code MCNPX [D. Pelowitz, MCNPX User's Manual Version 2.6.0, Los Alamos National Laboratory, 2008], and the fast electron temperature found to be 125 keV. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
16. Supra-thermal electron beam stopping power and guiding in dense plasmas.
- Author
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SANTOS, JOÃO JORGE, BATANI, D., BATON, S. D., BEG, F. N., CECCOTTI, T., DEBAYLE, A., DORCHIES, F., FEUGEAS, J.-L., FOURMENT, C., GREMILLET, L., HONRUBIA, J. J., HULIN, S., MORACE, A., NICOLAÏ, P., PÉREZ, F., SAWADA, H., SCHLENVOIGT, H.-P., TIKHONCHUK, V. T., VAISSEAU, X., and VAUZOUR, B.
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THERMAL electrons ,ELECTRON beams ,DENSE plasmas ,PHYSICS experiments ,PLASTIC foams ,OPTICAL self-focusing ,CURRENT density (Electromagnetism) - Abstract
Fast-electron beam stopping mechanisms in media ranging from solid to warm dense matter have been investigated experimentally and numerically. Laser-driven fast electrons have been transported through solid Al targets and shock-compressed Al and plastic foam targets. Their propagation has been diagnosed via rear-side optical self-emission and Kα X-rays from tracer layers. Comparison between measurements and simulations shows that the transition from collision-dominated to resistive field-dominated energy loss occurs for a fast-electron current density ~5 × 1011 A cm−2. The respective increases in the stopping power with target density and resistivity have been detected in each regime. Self-guided propagation over 200μm has been observed in radially compressed targets due to ~1kT magnetic fields generated by resistivity gradients at the converging shock front. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
17. Experiment in Planar Geometry for Shock Ignition Studies.
- Author
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Baton, S. D., Koenig, M., Brambrink, E., Schienvoigt, H. P., Rousseaux, C., Debras, G., Laffite, S., Loiseau, P., Philippe, F., Ribeyre, X., and Schultz, G.
- Subjects
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GEOMETRY , *NUMERICAL analysis , *COMPUTER simulation , *GROUP schemes (Mathematics) , *LASER-plasma interactions , *PLASMA confinement - Abstract
The capacity to launch a strong shock wave in a compressed target in the presence of large preplasma has been investigated experimentally and numerically in a planar geometry. The experiment was performed on the LULI 2000 laser facility using one laser beam to compress the target and a second to launch the strong shock simulating the intensity spike in die shock ignition scheme. Thanks to a large set of diagnostics, it has been possible to compare accurately experimental results with 2D numerical simulations. A good agreement has been observed even if a more detailed study of the laser-plasma interaction for the spike is necessary in order to confirm that this scheme is a possible alternative for inertial confinement fusion. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
18. A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths.
- Author
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Scott, R. H. H., Perez, F., Santos, J. J., Ridgers, C. P., Davies, J. R., Lancaster, K. L., Baton, S. D., Nicolai, Ph., Trines, R. M. G. M., Bell, A. R., Hulin, S., Tzoufras, M., Rose, S. J., and Norreys, P. A.
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ELECTRON transport ,ELECTRON energy states ,RELATIVISTIC kinematics ,LASER-plasma interactions ,DENSITY ,EXPERIMENTS ,ELECTRON beams - Abstract
A systematic experimental and computational investigation of the effects of three well characterized density scalelengths on fast electron energy transport in ultra-intense laser-solid interactions has been performed. Experimental evidence is presented which shows that, when the density scalelength is sufficiently large, the fast electron beam entering the solid-density plasma is best described by two distinct populations: those accelerated within the coronal plasma (the fast electron pre-beam) and those accelerated near or at the critical density surface (the fast electron main-beam). The former has considerably lower divergence and higher temperature than that of the main-beam with a half-angle of ∼20°. It contains up to 30% of the total fast electron energy absorbed into the target. The number, kinetic energy, and total energy of the fast electrons in the pre-beam are increased by an increase in density scalelength. With larger density scalelengths, the fast electrons heat a smaller cross sectional area of the target, causing the thinnest targets to reach significantly higher rear surface temperatures. Modelling indicates that the enhanced fast electron pre-beam associated with the large density scalelength interaction generates a magnetic field within the target of sufficient magnitude to partially collimate the subsequent, more divergent, fast electron main-beam. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
19. Laser-driven cylindrical compression of targets for fast electron transport study in warm and dense plasmas.
- Author
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Vauzour, B., Pérez, F., Volpe, L., Lancaster, K., Nicolaï, Ph., Batani, D., Baton, S. D., Beg, F. N., Benedetti, C., Brambrink, E., Chawla, S., Dorchies, F., Fourment, C., Galimberti, M., Gizzi, L. A., Heathcote, R., Higginson, D. P., Hulin, S., Jafer, R., and Köster, P.
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LASER beams ,ELECTRON transport ,HYDRODYNAMICS ,SIMULATION methods & models ,TEMPERATURE effect ,ELECTRIC conductivity ,ELECTRON configuration ,PHYSICS experiments ,ELECTRON distribution - Abstract
Fast ignition requires a precise knowledge of fast electron propagation in a dense hydrogen plasma. In this context, a dedicated HiPER (High Power laser Energy Research) experiment was performed on the VULCAN laser facility where the propagation of relativistic electron beams through cylindrically compressed plastic targets was studied. In this paper, we characterize the plasma parameters such as temperature and density during the compression of cylindrical polyimide shells filled with CH foams at three different initial densities. X-ray and proton radiography were used to measure the cylinder radius at different stages of the compression. By comparing both diagnostics results with 2D hydrodynamic simulations, we could infer densities from 2 to 11 g/cm3 and temperatures from 30 to 120 eV at maximum compression at the center of targets. According to the initial foam density, kinetic, coupled (sometimes degenerated) plasmas were obtained. The temporal and spatial evolution of the resulting areal densities and electrical conductivities allow for testing electron transport in a wide range of configurations. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
20. Reflectivity of stimulated Brillouin scattering in picosecond time scales.
- Author
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Labaune, C., Rozmus, Wojciech, Baldis, Hector A., Mounaix, Patrick, Pesme, Denis, Baton, S. D., LaFontaine, Bruno, Villeneuve, David M., and Enright, G. D.
- Published
- 1991
- Full Text
- View/download PDF
21. Study of stimulated Brillouin scattering driven by a 10-ps pump.
- Author
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Baldis, Hector A., Barr, H. C., Villeneuve, David M., Enright, G. D., LaFontaine, Bruno, Bernard, John E., Labaune, C., and Baton, S. D.
- Published
- 1990
- Full Text
- View/download PDF
22. Single-shot divergence measurements of a laser-generated relativistic electron beam.
- Author
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Perez, F., Baton, S. D., Koenig, M., Chen, C. D., Hey, D., Key, M. H., Le Pape, S., Ma, T., McLean, H. S., MacPhee, A. G., Patel, P. K., Ping, Y., Beg, F. N., Higginson, D. P., Murphy, C. W., Sawada, H., Westover, B., Yabuuchi, T., Akli, K. U., and Giraldez, E.
- Subjects
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LASER plasmas , *MONTE Carlo method , *SIMULATION methods & models , *IMAGING systems , *ELECTRON transport , *RELATIVISTIC particles , *ELECTRON beams , *FLUORESCENCE spectroscopy - Abstract
The relativistic electron transport induced by an ultraintense picosecond laser is experimentally investigated using an x-ray two-dimensional imaging system. Previous studies of the electron beam divergence [R. B. Stephens et al. Phys. Rev. E 69, 066414 (2004), for instance] were based on an x-ray imaging of a fluorescence layer buried at different depths in the target along the propagation axis. This technique required several shots to be able to deduce the divergence of the beam. Other experiments produced single-shot images in a one-dimensional geometry. The present paper describes a new target design producing a single-shot, two-dimensional image of the electrons propagating in the target. Several characteristics of the electron beam are extracted and discussed and Monte Carlo simulations provide a good understanding of the observed beam shape. The proposed design has proven to be efficient, reliable, and promising for further similar studies. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
23. Laser-driven fast electron dynamics in gaseous media under the influence of large electric fields.
- Author
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Batani, D., Baton, S. D., Manclossi, M., Piazza, D., Koenig, M., Benuzzi-Mounaix, A., Popescu, H., Rousseaux, C., Borghesi, M., Cecchetti, C., and Schiavi, A.
- Subjects
- *
PARTICLES (Nuclear physics) , *CATHODE rays , *ELECTRONS , *PHYSICAL & theoretical chemistry , *SHADOW-pictures - Abstract
We present the results of experiments performed at the LULI laboratory, using the 100 TW laser facility, on the study of the propagation of fast electrons in gas targets. The implemented diagnostics included chirped shadowgraphy and proton imaging. Proton images showed the presence of very large fields in the gas (produced by charge separation). In turn, these imply a strong inhibition of propagation, and a slowing down of the fast electron cloud as it penetrates in the gas. Indeed chirped shadowgraphy images show a reduction in time of the velocity of the electron cloud from the initial value, of the order of a fraction of c, over a time scale of a few picoseconds. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
24. Heating of solid target in electron refluxing dominated regime with ultra-intense laser.
- Author
-
Nakatsutsumi, M, Kodama, R, Aglitskiy, Y, Akli, K U, Batani, D, Baton, S D, Beg, F N, Benuzzi-Mounaix, A, Chen, S N, Clark, D, Davies, J R, Freeman, R R, Fuchs, J, Green, J S, Gregory, C D, Guillou, P, Habara, H, Heathcote, R, Hey, D S, and Highbarger, K
- Published
- 2008
- Full Text
- View/download PDF
25. Inhibition of fast electron energy deposition due to preplasma filling of cone-attached targets.
- Author
-
Baton, S. D., Koenig, M., Fuchs, J., Benuzzi-Mounaix, A., Guillou, P., Loupias, B., Vinci, T., Gremillet, L., Rousseaux, C., Drouin, M., Lefebvre, E., Dorchies, F., Fourment, C., Santos, J. J., Batani, D., Morace, A., Redaelli, R., Nakatsutsumi, M., Kodama, R., and Nishida, A.
- Subjects
- *
ELECTRONS , *LASER beams , *ELECTRON distribution , *CATHODE rays , *ELECTRON energy loss spectroscopy - Abstract
We present experimental and numerical results on the propagation and energy deposition of laser-generated fast electrons into conical targets. The first part reports on experimental measurements performed in various configurations in order to assess the predicted benefit of conical targets over standard planar ones. For the conditions investigated here, the fast electron-induced heating is found to be much weaker in cone-guided targets irradiated at a laser wavelength of 1.057 μm, whereas frequency doubling of the laser pulse permits us to bridge the disparity between conical and planar targets. This result underscores the prejudicial role of the prepulse-generated plasma, whose confinement is enhanced in conical geometry. The second part is mostly devoted to the particle-in-cell modeling of the laser-cone interaction. In qualitative agreement with the experimental data, the calculations show that the presence of a large preplasma leads to a significant decrease in the fast electron density and energy flux near the target rear side. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
26. Subfemtosecond, coherent, relativistic, and ballistic electron bunches generated at ω0 and 2ω0 in high intensity laser-matter interaction.
- Author
-
Popescu, H., Baton, S. D., Amiranoff, F., Rousseaux, C., Le Gloahec, M. Rabec, Santos, J. J., Gremillet, L., Koenig, M., Martinolli, E., Hall, T., Adam, J. C., Heron, A., and Batani, D.
- Subjects
- *
LASER beams , *CATHODE rays , *ULTRASHORT laser pulses , *IRRADIATION , *COHERENCE (Physics) , *RELATIVISTIC kinematics , *FEMTOCHEMISTRY - Abstract
Harmonics of the laser light have been observed from the rear side of solid targets irradiated by a laser beam at relativistic intensities. This emission evidences the acceleration of subfemtosecond electron bunches by the laser pulse in front of the target. These bunches emit coherent transition radiation (CTR) when passing through the back surface of the target. The spectral features of the signal recorded for targets of thicknesses up to several hundred microns are consistent with the electrons being accelerated by both the laser electric field—via vacuum heating and/or resonance absorption,—and the v×B component of the Lorentz force. The spatial study of the radiation shows that the relativistic electrons causing the CTR radiation are coherent and propagate ballistically through the target, originating from a source with a size of the order of the laser focal spot. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
27. Strong absorption, intense forward-Raman scattering and relativistic electrons driven by a short, high intensity laser pulse through moderately underdense plasmas.
- Author
-
Rousseaux, C., Rabec le Gloahec, M., Baton, S. D., Amiranoff, F., Fuchs, J., Gremillet, L., Adam, J. C., Héron, A., and Mora, P.
- Subjects
ULTRASHORT laser pulses ,PULSE generators ,RAMAN effect - Abstract
The propagation of a short and intense laser pulse (1.057 µm, 350 fs, 10[sup 17] W/cm²-2 ×10[sup 19]W/cm²) through preformed undercritical plasmas (≈5%-40% of n[sub c]) has been experimentally investigated on the 100-TW laser facility at the Laboratoire pour l'Utilisation des Lasers Intenses. The transmission and reflection of the 1 @m laser pulse, the forward- and backward-Raman (respectively, F-SRS and B-SRS) scattered light and the emission of fast electrons are reported. Significant absorption occurs in these plasmas, which is found to increase with the laser intensity. B-SRS is strongly driven at 10[sup 17] W/cm² and gradually decreases at higher intensities. It is shown that the transmission is low and only weakly dependent on the laser intensity. In contrast, the forward Raman scattering continuously increases with the laser intensity, up to 7% of the incident energy at 2 × 10[sup 19] W/cm² in the lowest density case. The relativistic electrons accelerated in the forward direction appear to be correlated with the F-SRS. The experimental data are discussed in the light of recent theoretical and numerical investigations, indicating that intense electron heating is likely to play a major role in the temporal growth or inhibition of the instabilities. The theoretical predictions are in agreement with the experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
28. Observation of the Langmuir decay instability driven by stimulated Raman scattering.
- Author
-
Baker, K. L., Drake, R. P., Bauer, B. S., Estabrook, K. G., Rubenchik, A. M., Labaune, C., Baldis, H. A., Renard, N., Baton, S. D., Schifano, E., Michard, A., Seka, W., and Bahr, R. E.
- Subjects
PLASMA frequencies ,RAMAN effect ,THOMSON scattering ,PLASMA waves - Abstract
Presents a measurement of the Langmuir wave spectrum driven by stimulated Raman scattering using Thomson scattering. Comparison of the Langmuir waves' parallel and antiparallel to the incident's wave vector; Description of the relative amplitude of the two Langmuir waves.
- Published
- 1997
- Full Text
- View/download PDF
29. Experimental investigation of stimulated Raman and Brillouin scattering instabilities driven by two successive collinear picosecond laser pulses.
- Author
-
Rousseaux, C., Baton, S. D., Bénisti, D., Gremillet, L., Loupias, B., Philippe, F., Tassin, V., Amiranoff, F., Kline, J. L., Montgomery, D. S., and Afeyan, B. B.
- Subjects
- *
STIMULATED Raman scattering , *ULTRASHORT laser pulses , *ELECTRON plasma - Abstract
Backward stimulated Raman and Brillouin scattering (SRS and SBS) are experimentally investigated by using two successive 1-µm, 1.5-ps FWHM laser pulses. The collinear pulses, separated by 3 or 6 ps and of moderate laser intensities (~2 × 1016Wcm-2), are fired into a preionized He plasma of density ~2.5-6 × 1019cm-3. The electron plasma waves and ion acoustic waves, respectively driven by SRS and SBS, are analyzed through space- and time-resolved Thomson scattering. Depending on the laser and plasma parameters, we observe the effect of the first pulse on the time-resolved SRS and SBS signals of the second pulse. The measurements are found to qualitatively agree with the results of a large-scale particle-in-cell simulation. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
30. Density and temperature characterization of long-scale length, near-critical density controlled plasma produced from ultra-low density plastic foam.
- Author
-
Chen, S. N., Iwawaki, T., Morita, K., Antici, P., Baton, S. D., Filippi, F., Habara, H., Nakatsutsumi, M., Nicolaï, P., Nazarov, W., Rousseaux, C., Starodubstev, M., Tanaka, K. A., and Fuchs, J.
- Published
- 2016
- Full Text
- View/download PDF
31. Recent experiments on electron transport in high-intensity laser matter interaction.
- Author
-
Baton, S. D., Batani, D., Manclossi, M., Morace, A., Piazza, D., Benuzzi-Mounaix, A., Koenig, M., Guillou, P., Loupias, B., Fuchs, J., Amiranoff, F., Rabec Le Gloahec, M., Popescu, H., Rousseaux, C., Borghesi, M., Cecchetti, C., Kodama, R., Norimatsu, T., Nakatsutsumi, M., and Aglitskiy, Y.
- Published
- 2005
- Full Text
- View/download PDF
32. Strong self-focusing in quasi-stationary laser plasmas.
- Author
-
Malka, V., Galloudec, N. Renard-Le, Hu¨ller, S., Pesme, D., Amiranoff, F., Baton, S. D., Modena, A., Mounaix, Ph., Rousseaux, C., and Salvati, M.
- Subjects
LASER plasmas ,BRILLOUIN scattering - Abstract
Collective Thomson scattering imaging has been used to study the propagation and self-focusing processes taking place during the interaction of a nanosecond laser beam with a preionized gas-jet plasma. The experiments have been carried out with a laser beam power P[sub L] exceeding greatly the critical power for ponderomotive self-focusing P[sub c]. It has been found that the position of the ion acoustic waves excited by stimulated Brillouin scattering depends only weakly on the initial focal position of the interaction laser beam. These results, together with theoretical and numerical modeling, demonstrate that in such a regime (P[sub L]/P[sub c]>1) self-focusing is the dominant mechanism governing the localization of the interaction processes. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
33. Study of Schlieren diagnostics to investigate filamentation in plasmas with long density scale lengths
- Author
-
Baton, S.-D., Labaune, C., Mathieussent, G., and Seka, W.
- Published
- 1989
- Full Text
- View/download PDF
34. Fine-Scale Spatial and Temporal Structures of Second-Harmonic Emission from an Underdense Plasma.
- Author
-
Baton, S. D., Baldis, H. A., Jalinaud, T., and Labaune, C.
- Published
- 1993
- Full Text
- View/download PDF
35. Experimental Evidence of Backward Raman Scattering Driven Cooperatively by Two Picosecond Laser Pulses Propagating Side by Side.
- Author
-
Rousseaux, C., Glize, K., Baton, S. D., Lancia, L., Bénisti, D., and Gremillet, L.
- Subjects
- *
RAMAN scattering , *ULTRASHORT laser pulses , *POLARIZATION (Nuclear physics) - Abstract
This Letter investigates experimentally the backward stimulated Raman scattering (SRS) of two copropagating, 1-μm wavelength, 1.5-ps duration laser pulses focused side by side, but not simultaneously, in a preformed underdense plasma. When the two lasers do not interact, one of the pulses (so-called strong) yields a large SRS reflectivity, while the other weak pulse is essentially ineffective as regards SRS. By contrast, the weak pulse shows significant SRS activity if it is launched in the plasma slightly after the strong one, and for time delays as large as about 15 ps. For crossed polarizations and a lateral distance of 80-90 μm, the time delay has to be larger than 3-4 ps for the weak pulse to be active, while it has just to be positive when the polarizations are parallel. The experimental results are discussed with the help of large-scale particle-in-cell simulations. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
36. Relativistic High-Current Electron-Beam Stopping-Power Characterization in Solids and Plasmas: Collisional Versus Resistive Effects.
- Author
-
Vauzour, B., Santos, J. J., Debayle, A., Hulin, S., Schlenvoigt, H. -P., Vaisseau, X., Batani, D., Baton, S. D., Honrubia, J. J., Nicolaï, Ph., Beg, F. N., Benocci, R., Chawla, S., Coury, M., Dorchies, F., Fourment, C., d'Humières, E., Jarrot, L. C., McKenna, P., and Rhee, Y. J.
- Subjects
- *
ELECTRON beams , *ELECTRIC properties of aluminum , *LASER plasmas , *CURRENT density (Electromagnetism) , *RELATIVISTIC astrophysics , *LASER pulses - Abstract
We present experimental and numerical results on intense-laser-pulse-produced fast electron beams transport through aluminum samples, either solid or compressed and heated by laser-induced planar shock propagation. Thanks to absolute Kα yield measurements and its very good agreement with results from numerical simulations, we quantify the collisional and resistive fast electron stopping powers: for electron current densities of ≈ 8 × 1010 A/cm2 they reach 1.5 keV/μm and 0.8 keV/μm, respectively. For higher current densities up to 1012 A/cm2, numerical simulations show resistive and collisional energy losses at comparable levels. Analytical estimations predict the resistive stopping power will be kept on the level of 1 keV/μm for electron current densities of 1014 A/cm2, representative of the full-scale conditions in the fast ignition of inertially confined fusion targets. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
37. Controlling Fast-Electron-Beam Divergence Using Two Laser Pulses.
- Author
-
Scot, R. H. H., Beaucourt, C., Schienvoigt, H.-P., Markey, K., Lancaster, K. L., Ridgers, C. P., Brenner, C. M., Pasley, J., Gray, R. J., Musgrave, I. O., Robinson, A. P. L., Li, K., Notley, M. M., Davies, J. R., Baton, S. D., Santos, J. J., Feugeas, J.-L., Nicolaï, Ph., Malka, G., and Tikhonchuk, V. T.
- Subjects
- *
ELECTRON beams , *LASER pulses , *PHYSICS experiments , *MAGNETIC fields , *CURRENT density (Electromagnetism) , *COMPARATIVE studies - Abstract
This Letter describes the first experimental demonstration of the guiding of a relativistic electron beam in a solid target using two colinear, relativistically intense, picosecond laser pulses. The first pulse creates a magnetic field that guides the higher-current, fast-electron beam generated by the second pulse. The effects of intensity ratio, delay, total energy, and intrinsic prepulse are examined. Thermal and Ka imaging show reduced emission size, increased peak emission, and increased total emission at delays of 4-6 ps, an intensity ratio of 10:1 (second:first) and a total energy of 186 J. In comparison to a single, high-contrast shot, the inferred fast-electron divergence is reduced by 2.7 times, while the fast-electron current density is increased by a factor of 1.8. The enhancements are reproduced with modeling and are shown to be due to the self-generation of magnetic fields. Such a scheme could be of considerable benefit to fast-ignition inertial fusion. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
38. Laser-driven shock waves studied by x-ray radiography.
- Author
-
Antonelli, L., Atzeni, S., Schiavi, A., Baton, S. D., Brambrink, E., Koenig, M., Rousseaux, C., Richetta, M., Batani, D., Forestier-Colleoni, P., Le Bel, E., Maheut, Y., Nguyen-Bui, T., Ribeyre, X., and Trela, J.
- Subjects
- *
RADIOGRAPHY , *SHOCK waves , *X-rays - Abstract
Multimegabar laser-driven shock waves are unique tools for studying matter under extreme conditions. Accurate characterization of shocked matter is for instance necessary for measurements of equation of state data or opacities. This paper reports experiments performed at the LULI facility on the diagnosis of shock waves, using x-ray-absorption radiography. Radiographs are analyzed using standard Abel inversion. In addition, synthetic radiographs, which also take into account the finite size of the x-ray source, are generated using density maps produced by hydrodynamic simulations. Reported data refer to both plane cylindrical targets and hemispherical targets. Evolution and deformation of the shock front could be followed using hydrodynamic simulations. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
39. Collimated Propagation of Fast Electron Beams Accelerated by High-Contrast Laser Pulses in Highly Resistive Shocked Carbon.
- Author
-
Vaisseau, X., Morace, A., Touati, M., Nakatsutsumi, M., Baton, S. D., Hulin, S., Nicolaï, Ph., Nuter, R., Batani, D., Beg, F. N., Breil, J., Fedosejevs, R., Feugeas, J.-L., Forestier-Colleoni, P., Fourment, C., Fujioka, S., Giuffrida, L., Kerr, S., McLean, H. S., and Sawada, H.
- Subjects
- *
CARBON , *ELECTRON beams , *LASER pulses - Abstract
Collimated transport of ultrahigh intensity electron current was observed in cold and in laser-shocked vitreous carbon, in agreement with simulation predictions. The fast electron beams were created by coupling high-intensity and high-contrast laser pulses onto copper-coated cones drilled into the carbon samples. The guiding mechanism--observed only for times before the shock breakout at the inner cone tip--is due to self-generated resistive magnetic fields of ~0.5-1 kT arising from the intense currents of fast electrons in vitreous carbon, by virtue of its specific high resistivity over the range of explored background temperatures. The spatial distribution of the electron beams, injected through the samples at different stages of compression, was characterized by side-on imaging of hard x-ray fluorescence. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
40. Publisher's Note: Experimental investigation of stimulated Raman and Brillouin scattering instabilities driven by two successive collinear picosecond laser pulses [Phys. Rev. E 93, 043209 (2016)].
- Author
-
Rousseaux C, Baton SD, Bénisti D, Gremillet L, Loupias B, Philippe F, Tassin V, Amiranoff F, Kline JL, Montgomery DS, and Afeyan BB
- Abstract
This corrects the article DOI: 10.1103/PhysRevE.93.043209.
- Published
- 2016
- Full Text
- View/download PDF
41. Controlling fast-electron-beam divergence using two laser pulses.
- Author
-
Scott RH, Beaucourt C, Schlenvoigt HP, Markey K, Lancaster KL, Ridgers CP, Brenner CM, Pasley J, Gray RJ, Musgrave IO, Robinson AP, Li K, Notley MM, Davies JR, Baton SD, Santos JJ, Feugeas JL, Nicolaï P, Malka G, Tikhonchuk VT, McKenna P, Neely D, Rose SJ, and Norreys PA
- Abstract
This Letter describes the first experimental demonstration of the guiding of a relativistic electron beam in a solid target using two colinear, relativistically intense, picosecond laser pulses. The first pulse creates a magnetic field that guides the higher-current, fast-electron beam generated by the second pulse. The effects of intensity ratio, delay, total energy, and intrinsic prepulse are examined. Thermal and Kα imaging show reduced emission size, increased peak emission, and increased total emission at delays of 4-6 ps, an intensity ratio of 10∶1 (second:first) and a total energy of 186 J. In comparison to a single, high-contrast shot, the inferred fast-electron divergence is reduced by 2.7 times, while the fast-electron current density is increased by a factor of 1.8. The enhancements are reproduced with modeling and are shown to be due to the self-generation of magnetic fields. Such a scheme could be of considerable benefit to fast-ignition inertial fusion.
- Published
- 2012
- Full Text
- View/download PDF
42. Magnetically guided fast electrons in cylindrically compressed matter.
- Author
-
Pérez F, Debayle A, Honrubia J, Koenig M, Batani D, Baton SD, Beg FN, Benedetti C, Brambrink E, Chawla S, Dorchies F, Fourment C, Galimberti M, Gizzi LA, Gremillet L, Heathcote R, Higginson DP, Hulin S, Jafer R, Koester P, Labate L, Lancaster KL, MacKinnon AJ, MacPhee AG, Nazarov W, Nicolai P, Pasley J, Ramis R, Richetta M, Santos JJ, Sgattoni A, Spindloe C, Vauzour B, Vinci T, and Volpe L
- Abstract
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 a collimated or scattered electron beam depending on the initial density and the compression timing. A numerical transport model shows that implosion-driven electrical resistivity gradients induce strong magnetic fields able to guide the electrons. The good agreement with measured beam sizes provides the first experimental evidence for fast-electron magnetic collimation in laser-compressed matter.
- Published
- 2011
- Full Text
- View/download PDF
43. Enhanced isochoric heating from fast electrons produced by high-contrast, relativistic-intensity laser pulses.
- Author
-
Perez F, Gremillet L, Koenig M, Baton SD, Audebert P, Chahid M, Rousseaux C, Drouin M, Lefebvre E, Vinci T, Rassuchine J, Cowan T, Gaillard SA, Flippo KA, and Shepherd R
- Abstract
Thin, mass-limited targets composed of V/Cu/Al layers with diameters ranging from 50 to 300 microm have been isochorically heated by a 300 fs laser pulse delivering up to 10 J at 2x10{19} W/cm{2} irradiance. Detailed spectral analysis of the Cu x-ray emission indicates that the highest temperatures, of the order of 100 eV, have been reached when irradiating the smallest targets with a high-contrast, frequency-doubled pulse despite a reduced laser energy. Collisional particle-in-cell simulations confirm the detrimental influence of the preformed plasma on the bulk target heating.
- Published
- 2010
- Full Text
- View/download PDF
44. Experimental evidence of predominantly transverse electron plasma waves driven by stimulated Raman scattering of picosecond laser pulses.
- Author
-
Rousseaux C, Baton SD, Bénisti D, Gremillet L, Adam JC, Héron A, Strozzi DJ, and Amiranoff F
- Abstract
We report on highly time- and space-resolved measurements of the evolution of electron plasma waves driven by stimulated Raman scattering of a picosecond, single laser speckle propagating through a preformed underdense plasma. Two-dimensional Thomson scatter spectra indicate that the dominant waves have significant transverse components. These results are supported by particle-in-cell simulations which pinpoint the dominant role of the wave front bowing and of secondary nonlinear electrostatic instabilities in the evolution of the plasma waves.
- Published
- 2009
- Full Text
- View/download PDF
45. Enhanced hot-electron localization and heating in high-contrast ultraintense laser irradiation of microcone targets.
- Author
-
Rassuchine J, d'Humières E, Baton SD, Guillou P, Koenig M, Chahid M, Perez F, Fuchs J, Audebert P, Kodama R, Nakatsutsumi M, Ozaki N, Batani D, Morace A, Redaelli R, Gremillet L, Rousseaux C, Dorchies F, Fourment C, Santos JJ, Adams J, Korgan G, Malekos S, Hansen SB, Shepherd R, Flippo K, Gaillard S, Sentoku Y, and Cowan TE
- Abstract
We report experiments demonstrating enhanced coupling efficiencies of high-contrast laser irradiation to nanofabricated conical targets. Peak temperatures near 200 eV are observed with modest laser energy (10 J), revealing similar hot-electron localization and material heating to reduced mass targets (RMTs), despite having a significantly larger mass. Collisional particle-in-cell simulations attribute the enhancement to self-generated resistive (approximately 10 MG) magnetic fields forming within the curvature of the cone wall, which confine energetic electrons to heat a reduced volume at the tip. This represents a different electron confinement mechanism (magnetic, as opposed to electrostatic sheath confinement in RMTs) controllable by target shape.
- Published
- 2009
- Full Text
- View/download PDF
46. Transient development of backward stimulated Raman and Brillouin scattering on a picosecond time scale measured by subpicosecond thomson diagnostic.
- Author
-
Rousseaux C, Gremillet L, Casanova M, Loiseau P, Rabec Le Gloahec M, Baton SD, Amiranoff F, Adam JC, and Héron A
- Abstract
The excitation and the relaxation of the plasma waves and ion acoustic waves (IAW), respectively, driven by stimulated Raman (SRS) and Brillouin (SBS) backscatterings have been experimentally investigated with short-pulse lasers. The spectra have been obtained with a 0.3 ps time resolution. It is shown that SRS develops before SBS and suddenly decays around the peak of the pump, as the IAW reaches saturation. On this short time scale, electron kinetic effects play a major role for SRS saturation, contrary to ion dynamics. These results are supported by particle-in-cell simulations.
- Published
- 2006
- Full Text
- View/download PDF
47. Fast-electron transport and heating of solid targets in high-intensity laser interactions measured by K alpha fluorescence.
- Author
-
Martinolli E, Koenig M, Baton SD, Santos JJ, Amiranoff F, Batani D, Perelli-Cippo E, Scianitti F, Gremillet L, Mélizzi R, Decoster A, Rousseaux C, Hall TA, Key MH, Snavely R, MacKinnon AJ, Freeman RR, King JA, Stephens R, Neely D, and Clarke RJ
- Abstract
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 fast-electron propagation in multilayered targets. Target heating was measured from ionization-shifted K alpha emission. Data show a 200 microm fast-electron range in solid Al. The relative intensities of spectrally shifted Al K alpha lines imply a mean temperature of a few tens of eV up to a 100 microm depth. Experimental results suggest refluxing of the electron beam at target rear side. They were compared with the predictions of both a collisional Monte Carlo and a collisional-electromagnetic, particle-fluid transport code. The validity of the code modeling of heating in such highly transient conditions is discussed.
- Published
- 2006
- Full Text
- View/download PDF
48. Ultraintense laser-produced fast-electron propagation in gas jets.
- Author
-
Batani D, Baton SD, Manclossi M, Santos JJ, Amiranoff F, Koenig M, Martinolli E, Antonicci A, Rousseaux C, Le Gloahec MR, Hall T, Malka V, Cowan TE, King J, Freeman RR, Key M, and Stephens R
- Abstract
We study the propagation of fast electrons in a gas at different densities. A large relativistic electron current is produced by focusing a short-pulse ultrahigh-intensity laser on a metallic target. It then propagates in a gas jet placed behind the foil. Shadowgraphy in the gas shows an electron cloud moving at sub-relativistic average velocities. The experiment shows (i) the essential role of the density of background material for allowing propagation of fast electrons, (ii) the importance of the ionization phase which produces free electrons available for the return current, and (iii) the effect of electrostatic fields on fast-electron propagation.
- Published
- 2005
- Full Text
- View/download PDF
49. Fast electron heating of a solid target in ultrahigh-intensity laser pulse interaction.
- Author
-
Martinolli E, Koenig M, Amiranoff F, Baton SD, Gremillet L, Santos JJ, Hall TA, Rabec-Le-Gloahec M, Rousseaux C, and Batani D
- Abstract
We report one of the first measurements of induced heating due to the transport of a fast electron beam generated by an ultrashort pulse laser interaction with solid targets. Rear-side optical reflectivity and emissivity have been used as diagnostics for the size and temperature of the heated zone. A narrow spot has been observed of the order of the laser focus size. Values up to approximately 10 eV at the target back surface were inferred from the experimental data and compared with the predictions of a hybrid collisional-electromagnetic transport simulation.
- Published
- 2004
- Full Text
- View/download PDF
50. K(alpha) fluorescence measurement of relativistic electron transport in the context of fast ignition.
- Author
-
Stephens RB, Snavely RA, Aglitskiy Y, Amiranoff F, Andersen C, Batani D, Baton SD, Cowan T, Freeman RR, Hall T, Hatchett SP, Hill JM, Key MH, King JA, Koch JA, Koenig M, MacKinnon AJ, Lancaster KL, Martinolli E, Norreys P, Perelli-Cippo E, Rabec Le Gloahec M, Rousseaux C, Santos JJ, and Scianitti F
- Abstract
Electron transport within solid targets, irradiated by a high-intensity short-pulse laser, has been measured by imaging K(alpha) radiation from high- Z layers (Cu, Ti) buried in low- Z (CH, Al) foils. Although the laser spot is approximately 10 microm [full width at half maximum (FWHM)], the electron beam spreads to > or =70 microm FWHM within <20 microm of penetration into an Al target then, at depths >100 microm, diverges with a 40 degree spreading angle. Monte Carlo and analytic models are compared to our data. We find that a Monte Carlo model with a heuristic model for the electron injection gives a reasonable fit with our data.
- Published
- 2004
- Full Text
- View/download PDF
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