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R. H. H. Scott,
E. L. Clark,
F. Perez,
M. J. V Streeter,
J. R. Davies,
H. -P. Schlenvoigt,
J. J. Santos,
S. Hulin,
K. L. Lancaster, S. D. Baton,
S. J. Rose,
P. A. Norreys
[show abstract]
[hide abstract]
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 back-out the fast electron spectrum and
laser energy absorbed into 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 was interpreted using the 3-spatial-dimension Monte Carlo
code MCNPX (Pelowitz 2008), and the fast electron temperature found to be 125
keV.
04/2013;
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S. Jacquemot,
F. Amiranoff, S. D. Baton,
J. C. Chanteloup,
C. Labaune,
M. Koenig,
D. T. Michel,
F. Perez,
H. P. Schlenvoigt,
B. Canaud, [......],
D. Batani,
J. R. Davies,
F. Fiuza,
R. A. Fonseca,
L. O. Silva,
L. A. Gizzi,
P. Koester,
L. Labate,
J. Badziak,
O. Klimo
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B Vauzour,
J J Santos,
A Debayle,
S Hulin,
H-P Schlenvoigt,
X Vaisseau,
D Batani, S D Baton,
J J Honrubia,
Ph Nicolaï, [......],
M Coury,
F Dorchies,
C Fourment,
E d'Humières,
L C Jarrot,
P McKenna,
Y J Rhee,
V T Tikhonchuk,
L Volpe,
V Yahia
[show abstract]
[hide abstract]
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 K_{α} 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 ≈8×10^{10} A/cm^{2} they reach 1.5 keV/μm and 0.8 keV/μm, respectively. For higher current densities up to 10^{12} A/cm^{2}, 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 10^{14} A/cm^{2}, representative of the full-scale conditions in the fast ignition of inertially confined fusion targets.
Physical Review Letters 12/2012; 109(25):255002. · 7.37 Impact Factor
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R H H Scott,
C Beaucourt,
H-P Schlenvoigt,
K Markey,
K L Lancaster,
C P Ridgers,
C M Brenner,
J Pasley,
R J Gray,
I O Musgrave, [......], S D Baton,
J J Santos,
J-L Feugeas,
Ph Nicolaï,
G Malka,
V T Tikhonchuk,
P McKenna,
D Neely,
S J Rose,
P A Norreys
[show abstract]
[hide abstract]
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.
Physical Review Letters 07/2012; 109(1):015001. · 7.37 Impact Factor
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R. H. H. Scott,
F. Perez,
J. J. Santos,
C. P. Ridgers,
J. R. Davies,
K. L. Lancaster, S. D. Baton,
Ph. Nicolai,
R. M. G. M. Trines,
A. R. Bell,
S. Hulin,
M. Tzoufras,
S. J. Rose,
P. A. Norreys
Physics of Plasmas 04/2012; 19(5):053104-13. · 2.15 Impact Factor
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S. D. Baton,
M. Koenig,
J. Fuchs,
L. Gremillet,
C. Rousseaux,
D. Batani,
A. Morace,
M. Nakatsutsumi,
R. Kodama,
T. Norimatsu,
A. Nishida,
F. Dorchies,
C. Fourment,
J. J. Santos,
J. Rassuchine,
T. Cowan
[show abstract]
[hide abstract]
ABSTRACT: We present experimental and numerical results obtained at LULI (Laboratoire pour l’Utilisation des Lasers intenses) on propagation and energy deposition of laser-generated fast electrons into conical targets. The experimental measurements
were performed by means of several diagnostics in order to assess the predicted benefit of conical targets over standard planar
ones. Various configurations have been tried, regarding the laser parameters with the aim of optimizing the laser-to-target
coupling. Our best results have been obtained when the laser was frequency-doubled at 0.53 μm, corresponding to interaction
conditions without laser pedestal due to the ASE (Amplified Spontaneous Emission). Our data pinpoint the detrimental influence of the pre-plasma generated by the laser pedestal at 1.057 μm, whose confinement
is enhanced in conical geometry as evidenced by shadowgraphic measurements which is also confirmed by 2D Cu-Ka transverse images obtained from Cu cones. The consequence is the filling of the cone, preventing the laser beam from efficiently
reaching the cone tip. These experimental results are compared to 2D PIC simulations modeling of the laser-cone interaction.
The European Physical Journal Special Topics 04/2012; 175(1):77-82. · 1.56 Impact Factor
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F Pérez,
A Debayle,
J Honrubia,
M Koenig,
D Batani, S D Baton,
F N Beg,
C Benedetti,
E Brambrink,
S Chawla, [......],
P Nicolai,
J Pasley,
R Ramis,
M Richetta,
J J Santos,
A Sgattoni,
C Spindloe,
B Vauzour,
T Vinci,
L Volpe
[show abstract]
[hide abstract]
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.
Physical Review Letters 08/2011; 107(6):065004. · 7.37 Impact Factor
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B. Vauzour,
F. Pérez,
L. Volpe,
K. Lancaster,
Ph. Nicolaï,
D. Batani, S. D. Baton,
F. N. Beg,
C. Benedetti,
E. Brambrink, [......],
A. J. MacKinnon,
A. G. MacPhee,
W. Nazarov,
J. Pasley,
C. Regan,
X. Ribeyre,
M. Richetta,
G. Schurtz,
A. Sgattoni,
J. J. Santos
[show abstract]
[hide abstract]
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.
Physics of Plasmas 04/2011; 18(4):043108-043108-9. · 2.15 Impact Factor
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B Vauzour,
J J Santos,
D Batani, S D Baton,
M Koenig,
Ph. Nicolai,
F Perez,
F N Beg,
C Benedetti,
R Benocci, [......],
X Ribeyre,
M Richetta,
F Serres,
H -P Schlenvoigt,
G Schurtz,
A Sgattoni,
C Spindloe,
X Vaisseau,
L Volpe,
V Yahia
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/2011; 653(1):176-180. · 1.21 Impact Factor
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S. Jacquemot,
F. Amiranoff, S.D. Baton,
J.C. Chanteloup,
C. Labaune,
M. Koenig,
D.T. Michel,
F. Perez,
H.P. Schlenvoigt,
B. Canaud,
C. Cherfils Clérouin,
G. Debras,
S. Depierreux,
J. Ebrardt,
D. Juraszek,
S. Lafitte,
P. Loiseau,
et al
[show abstract]
[hide abstract]
ABSTRACT: Demonstrating ignition and net energy gain in the near future on MJ-class laser facilities will be a major step towards determining the feasibility of Inertial Fusion Energy (IFE), in Europe as in the United States. The current status of the French Laser MégaJoule (LMJ) programme, from the laser facility construction to the indirectly driven central ignition target design, is presented, as well as validating experimental campaigns, conducted, as part of this programme, on various laser facilities. However, the viability of the IFE approach strongly depends on our ability to address the salient questions related to efficiency of the target design and laser driver performances. In the overall framework of the European HiPER project, two alternative schemes both relying on decoupling target compression and fuel heating—fast ignition (FI) and shock ignition (SI)—are currently considered. After a brief presentation of the HiPER project's objectives, FI and SI target designs are discussed. Theoretical analysis and 2D simulations will help to understand the unresolved key issues of the two schemes. Finally, the on-going European experimental effort to demonstrate their viability on currently operated laser facilities is described.
Nuclear Fusion 01/2011; 51:094025. · 4.09 Impact Factor
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J J Santos,
D Batani,
P McKenna, S D Baton,
F Dorchies,
A Dubrouil,
C Fourment,
S Hulin,
E d'Humières,
P H Nicolaï,
L Gremillet,
A Debayle,
J J Honrubia,
P Carpeggiani,
M Veltcheva,
M N Quinn,
E Brambrink,
V Tikhonchuk
[show abstract]
[hide abstract]
ABSTRACT: We present results from an experimental characterization of fast electron transport in high density plasmas created by 1D shock wave compression. The Kα fluorescence from a Cu layer embedded in Al or CH foil targets is measured. We use long laser pulses (LP) with 180 J, 1.5 ns, 0.53μm to compress the foils by shock wave propagation to 2-3 times their solid density and heat them to ~ 4eV (close to the Fermi temperature). A counter-propagating high-intensity short laser pulse (SP), with 40 J, 1 ps, 57×1019 Wcm−2, generates intense currents of fast electrons which propagate through the deep regions of the target just before shock breakthrough. The results are compared to the uncompressed, solid density case (without the LP beam). The complete set of measurements is compared to numerical results, including a 2D hydrodynamic description of the compression and pre-pulse effects, 2D PIC simulations of the SP beam interaction and both hybrid and PIC simulations of the electron transport in the target depth and sheaths. In the case of the non-compressed targets we need to take fast electron refluxing into account to reproduce the experimental results. By exploring the domain of warm temperatures, we identify a regime for the incident fast electron current density, 1010 < jh < 1012 Acm−2, for which the collective mechanisms of electron transport differs appreciably between solid density and compressed matter.
Journal of Physics Conference Series 09/2010; 244(2):022060.
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F Perez,
L Gremillet,
M Koenig, S D Baton,
P Audebert,
M Chahid,
C Rousseaux,
M Drouin,
E Lefebvre,
T Vinci,
J Rassuchine,
T Cowan,
S A Gaillard,
K A Flippo,
R Shepherd
[show abstract]
[hide abstract]
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.
Physical Review Letters 02/2010; 104(8):085001. · 7.37 Impact Factor
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F Perez, S D Baton,
M Koenig,
C D Chen,
D Hey,
M H Key,
S Le Pape,
T Ma,
H S McLean,
A G MacPhee, [......],
L Gremillet,
E Lefebvre,
R R Freeman,
G E Kemp,
A G Krygier,
L D Van Woerkom,
R Fedosejevs,
R H Friesen,
Y Y Tsui,
D Turnbull
[show abstract]
[hide abstract]
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.
Physics of Plasmas 01/2010; 17(11):113106 (7 pp.). · 2.15 Impact Factor
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F Perez,
M Koenig,
D Batani, S D Baton,
F N Beg,
C Benedetti,
E Brambrink,
S Chawla,
F Dorchies,
C Fourment, [......],
W Nazarov,
P Nicolai,
J Pasley,
A Ravasio,
M Richetta,
J J Santos,
A Sgattoni,
C Spindloe,
B Vauzour,
L Volpe
Plasma Physics and Controlled Fusion 12/2009; 51(12). · 2.42 Impact Factor
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[show abstract]
[hide abstract]
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.
Physical Review Letters 06/2009; 102(18):185003. · 7.37 Impact Factor
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J Rassuchine,
E d'Humières, S D Baton,
P Guillou,
M Koenig,
M Chahid,
F Perez,
J Fuchs,
P Audebert,
R Kodama, [......],
J J Santos,
J Adams,
G Korgan,
S Malekos,
S B Hansen,
R Shepherd,
K Flippo,
S Gaillard,
Y Sentoku,
T E Cowan
[show abstract]
[hide abstract]
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.
Physical Review E 04/2009; 79(3 Pt 2):036408. · 2.26 Impact Factor
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D. Batani, S. D. Baton,
M. Manclossi,
D. Piazza,
M. Koenig,
A. Benuzzi-Mounaix,
H. Popescu,
C. Rousseaux,
M. Borghesi,
C. Cecchetti,
A. Schiavi
[show abstract]
[hide abstract]
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.
Physics of Plasmas 03/2009; 16(3):033104-033104-6. · 2.15 Impact Factor
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J L Kline,
D S Montgomery,
C Rousseaux, S D Baton,
V Tassin,
R A Hardin,
K A Flippo,
R P Johnson,
T Shimada,
L Yin,
B J Albright,
H A Rose,
And F Amiranoff
[show abstract]
[hide abstract]
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 of these laser plasma instabilities impacts the current inertial confinement fusion ignition designs and could potentially impact fast ignition when higher energy lasers are used with longer pulse durations (.1 kJ and .1 ps). Using short laser pulses, experiments can be modeled over the entire interaction time of the laser using particle-in-cell codes to validate our understanding quantitatively. Experiments have been conducted at the Trident laser facility and the Laboratoire pour l'Utilisation des Lasers Intenses (LULI) to investigate stimulated Raman scattering near the threshold of the instability using 527 nm and 1059 nm laser light, respectively, with 1.5–3.0 ps pulses. In both experiments, the interaction beam was focused into pre-ionized helium gas-jet plasma. Measurements of the reflectivity as a function of intensity and kl D were completed at the Trident laser facility, where k is the electron plasma wave number and l D is the plasma Debye length. At LULI, a 300 fs Thomson scattering probe is used to directly measure the density fluctuations of the driven electron plasma and ion acoustic waves. Work is currently underway comparing the results of the experiments with simulations using the VPIC particle-in-cell code. Details of the experimental results are presented in this manuscript.
Laser and Particle Beams 01/2009; 27(27):185-190. · 1.62 Impact Factor
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M Nakatsutsumi,
R Kodama,
Y Aglitskiy,
K U Akli,
D Batani, S D Baton,
F N Beg,
A Benuzzi-Mounaix,
S N Chen,
D Clark, [......],
D Piazza,
C Rousseaux,
R B Stephans,
M Storm,
M Tampo,
W Theobald,
L V Woerkom,
R L Weber,
M S Wei,
N C Woolsey
[show abstract]
[hide abstract]
ABSTRACT: Propagation of electron beams generated in laser-plasma interactions is strongly influenced by self-induced electrostatic fields at target-vacuum interfaces, resulting the refluxing of electrons. We confirmed the refluxing and propagation of electrons with three different kinds of target configurations; thin-wide foil, thin-narrow foil, and long-wire geometry. Enhancement of target heating, effective guiding and collimation of high density MeV electrons were observed.
Journal of Physics Conference Series 06/2008; 112(2):022063.
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S. D. Baton,
M. Koenig,
J. Fuchs,
A. Benuzzi-Mounaix,
P. Guillou,
B. Loupias,
T. Vinci,
L. Gremillet,
C. Rousseaux,
M. Drouin, [......],
A. Morace,
R. Redaelli,
M. Nakatsutsumi,
R. Kodama,
A. Nishida,
N. Ozaki,
T. Norimatsu,
Y. Aglitskiy,
S. Atzeni,
A. Schiavi
[show abstract]
[hide abstract]
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.
Physics of Plasmas 04/2008; 15(4):042706-042706-11. · 2.15 Impact Factor
