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371 results on '"Pépin H"'

1. Longitudinal proton probing of ultrafast and high-contrast laser-solid interactions

Author

Albertazzi B., Antici P., Bocker J., Borghesi M., Chen S., Dervieux V., d'Humières E., Lancia L., Nakatsutsumi M., Shepherd R., Romagnagni L., Sentoku Y., Swantusch M., Willi O., Pépin H., and Fuchs J.

Subjects
Physics, QC1-999
Abstract

We have performed an experiment aimed at measuring self-generated magnetic fields produced in solids by high electron currents following high-intensity and high contrast short-pulse laser irradiation. This was done using longitudinal high resolution proton deflectometry. The experiment was performed at the Titan-JLF laser facility with a high-power short-pulse beam (700 fs, ∼ 110 J) split into two beams irradiating two solid targets. One beam is used for the generation of protons and the other beam for the generation of the ultra-high currents of electrons and of the associated magnetic fields. This capability allows us to study the spatio-temporal evolution of the magnetic fields and its dependence on the laser intensity and target material.

Published
2013
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2. Acceleration of collimated 45 MeV protons by collisionless shocks driven in low-density, large-scale gradient plasmas by a 10^20 W/cm^2, 1 micron wavelength laser

Author

Antici, P., Boella, E., Chen, S. N., Andrews, D. S., Barberio, M., Böker, J., Cardelli, F., Feugeas, J. L., Glesser, M., Nicolaï, P., Romagnani, L., Sciscio, M., Starodubtsev, M., Willi, O., Kieffer, J. C., Tikhonchuk, V., Pépin, H., Silva, L. O., Humières, E. d, and Fuchs, J.

Subjects
Physics - Plasma Physics
Abstract

A new type of proton acceleration stemming from large-scale gradients, low-density targets, irradiated by an intense near-infrared laser is observed. The produced protons are characterized by high-energies (with a broad spectrum), are emitted in a very directional manner, and the process is associated to relaxed laser (no need for high-contrast) and target (no need for ultra-thin or expensive targets) constraints. As such, this process appears quite effective compared to the standard and commonly used Target Normal Sheath Acceleration technique (TNSA), or more exploratory mechanisms like Radiation Pressure Acceleration (RPA). The data are underpinned by 3D numerical simulations which suggest that in these conditions Low Density Collisionless Shock Acceleration (LDCSA) is at play, which combines an initial Collisionless Shock Acceleration (CSA) to a boost procured by a TNSA-like sheath field in the downward density ramp of the target, which leads to an overall broad spectrum. Experiments performed at 10^20 W/cm^2 laser intensity show that LDCSA can accelerate, from ~1% critical density, mm-scale targets, up to 5x10^9 protons/MeV/sr/J with energies up to 45(+/- 5) MeV in a collimated (~6$^\circ$ half-angle) manner.

Published
2017

3. Laboratory unravelling of matter accretion in young stars

Author

Revet, G., Chen, S. N., Bonito, R., Khiar, B., Filippov, E., Argiroffi, C., Higginson, D. P., Orlando, S., Béard, J., Blecher, M., Borghesi, M., Burdonov, K., Khaghani, D., Naughton, K., Pépin, H., Portugall, O., Riquier, R., Rodriguez, R., Ryazantsev, S. N., Skobelev, I. Yu., Soloviev, A., Willi, O., Pikuz, S., Ciardi, A., and Fuchs, J.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Physics - Plasma Physics
Abstract

Accretion dynamics in the forming of young stars is still object of debate because of limitations in observations and modelling. Through scaled laboratory experiments of collimated plasma accretion onto a solid in the presence of a magnetic field, we open first window on this phenomenon by tracking, with spatial and temporal resolution, the dynamics of the system and simultaneously measuring multiband emissions. We observe in these experiments that matter, upon impact, is laterally ejected from the solid surface, then refocused by the magnetic field toward the incoming stream. Such ejected matter forms a plasma shell that envelops the shocked core, reducing escaped X-ray emission. This demonstrates one possible structure reconciling current discrepancies between mass accretion rates derived from X-ray and optical observations.

Published
2017

4. Collimated protons accelerated from an overdense gas jet irradiated by a 1 micron wavelength high-intensity short-pulse laser

Author

Chen, S. N., Vranic, M., Gangolf, T., Boella, E., Antici, P., Bailly-Grandvaux, M., Loiseau, P., Pépin, H., Revet, G., Santos, J. J., Schroer, A. M., Starodubtsev, M., Willi, O., Silva, L. O., Humières, E. d, and Fuchs, J.

Subjects
Physics - Plasma Physics
Abstract

We have investigated proton acceleration in the forward direction from a near-critical density hydrogen gas jet target irradiated by a high intensity (10^18 W/cm^2), short-pulse (5 ps) laser with wavelength of 1.054 micron. We observe the signature of shock acceleration driven by the laser pulse, leading to monoenergetic proton beams with small divergence in addition to the commonly used electron-sheath driven proton acceleration. The proton energies we obtained are modest (~MeV), but prospects for improvement are offered through tailoring the gas jet density profile. Also, we observe that this mechanism is very robust in producing those beams and thus can be considered as a future candidate in laser-driven ion sources driven by the upcoming next generation of multi-PW near-infrared lasers.

Published
2017

5. Experimental evidence for the enhanced and reduced stopping regimes for protons propagating through hot plasmas.

Author

Chen, SN, Atzeni, S, Gangolf, T, Gauthier, M, Higginson, DP, Hua, R, Kim, J, Mangia, F, McGuffey, C, Marquès, J-R, Riquier, R, Pépin, H, Shepherd, R, Willi, O, Beg, FN, Deutsch, C, and Fuchs, J

Abstract

Our understanding of the dynamics of ion collisional energy loss in a plasma is still not complete, in part due to the difficulty and lack of high-quality experimental measurements. These measurements are crucial to benchmark existing models. Here, we show that such a measurement is possible using high-flux proton beams accelerated by high intensity short pulse lasers, where there is a high number of particles in a picosecond pulse, which is ideal for measurements in quickly expanding plasmas. By reducing the energy bandwidth of the protons using a passive selector, we have made proton stopping measurements in partially ionized Argon and fully ionized Hydrogen plasmas with electron temperatures of hundreds of eV and densities in the range 1020-1021 cm-3. In the first case, we have observed, consistently with previous reports, enhanced stopping of protons when compared to stopping power in non-ionized gas. In the second case, we have observed for the first time the regime of reduced stopping, which is theoretically predicted in such hot and fully ionized plasma. The versatility of these tunable short-pulse laser based ion sources, where the ion type and energy can be changed at will, could open up the possibility for a variety of ion stopping power measurements in plasmas so long as they are well characterized in terms of temperature and density. In turn, these measurements will allow tests of the validity of existing theoretical models.

Published
2018

7. Astrophysics of magnetically collimated jets generated from laser-produced plasmas

Author

Ciardi, A., Vinci, T., Fuchs, J., Albertazzi, B., Riconda, C., Pépin, H., and Portugall, O.

Subjects
Physics - Plasma Physics, Astrophysics - Solar and Stellar Astrophysics
Abstract

The generation of astrophysically relevant jets, from magnetically collimated, laser-produced plasmas, is investigated through three-dimensional, magneto-hydrodynamic simulations. We show that for laser intensities I ~ 10^12 - 10^14 W/cm^2, a magnetic field in excess of ~ 0.1 MG, can collimate the plasma plume into a prolate cavity bounded by a shock envelope with a standing conical shock at its tip, which re-collimates the flow into a super magneto-sonic jet beam. This mechanism is equivalent to astrophysical models of hydrodynamic inertial collimation, where an isotropic wind is focused into a jet by a confining circumstellar torus-like envelope. The results suggest an alternative mechanism for a large-scale magnetic field to produce jets from wide-angle winds. (abridged version), Comment: Accepted for publication in Physical Review Letters. 5 pages, 4 figures

Published
2012
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12. Laboratory formation of a scaled protostellar jet by coaligned poloidal magnetic field

Author

Albertazzi, B., Ciardi, A., Nakatsutsumi, M., Vinci, T., Béard, J., Bonito, R., Billette, J., Borghesi, M., Burkley, Z., Chen, S. N., Cowan, T. E., Herrmannsdörfer, T., Higginson, D. P., Kroll, F., Pikuz, S. A., Naughton, K., Romagnani, L., Riconda, C., Revet, G., Riquier, R., Schlenvoigt, H.-P., Skobelev, I. Yu., Faenov, A.Ya., Soloviev, A., Huarte-Espinosa, M., Frank, A., Portugall, O., Pépin, H., and Fuchs, J.

Published
2014

15. LAB ASTROPHYSICS: Laboratory formation of a scaled protostellar jet by coaligned poloidal magnetic field

Author

Albertazzi, B., Ciardi, A., Nakatsutsumi, M., Vinci, T., Béard, J., Bonito, R., Billette, J., Borghesi, M., Burkley, Z., Chen, S. N., Cowan, T. E., Herrmannsdörfer, T., Higginson, D. P., Kroll, F., Pikuz, S. A., Naughton, K., Romagnani, L., Riconda, C., Revet, G., Riquier, R., Schlenvoigt, H.-P., Skobelev, I. Yu., Faenov, A. Ya., Soloviev, A., Huarte-Espinosa, M., Frank, A., Portugall, O., Pépin, H., and Fuchs, J.

Published
2014
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16. Ultra-low emittance, high current proton beams produced with a laser-virtual cathode sheath accelerator

Author

Cowan, T.E., Fuchs, J., Ruhl, H., Sentoku, Y., Kemp, A., Audebert, P., Roth, M., Stephens, R., Barton, I., Blazevic, A., Brambrink, E., Cobble, J., Fernández, J.C., Gauthier, J.-C., Geissel, M., Hegelich, M., Kaae, J., Karsch, S., Le Sage, G.P., Letzring, S., Manclossi, M., Meyroneinc, S., Newkirk, A., Pépin, H., and Renard-LeGalloudec, N.

Published
2005
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18. Plasma Physics with Ultra-Short and Ultra-Intense Laser Pulses

Author

Johnston, T. W., primary, Beaudoin, Y., additional, Chaker, M., additional, Côté, C. Y., additional, Kieffer, J. C., additional, Matte, J. P., additional, Pépin, H., additional, Chien, C. Y., additional, Coe, S., additional, Mourou, G., additional, and Umstadter, D., additional

Published
1993
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19. Collimated protons accelerated from an overdense gas jet irradiated by a 1 µm wavelength high-intensity short-pulse laser

Author

Chen, S. N., Vranic, M., Gangolf, T., Boella, E., Antici, P., Bailly-Grandvaux, M., Loiseau, P., Pépin, H., Revet, G., Santos, J. J., Schroer, A. M., Starodubtsev, Mikhail, Willi, O., Silva, L. O., d’Humières, E., and Fuchs, J.

Subjects
Proton acceleration, Collisionless Shock Acceleration mechanism, multi-PW near-infrared lasers, lcsh:R, lcsh:Medicine, Physics::Accelerator Physics, lcsh:Q, lcsh:Science, Article
Abstract

We have investigated proton acceleration in the forward direction from a near-critical density hydrogen gas jet target irradiated by a high intensity (1018 W/cm2), short-pulse (5 ps) laser with wavelength of 1.054 μm. We observed the signature of the Collisionless Shock Acceleration mechanism, namely quasi-monoenergetic proton beams with small divergence in addition to the more commonly observed electron-sheath driven proton acceleration. The proton energies we obtained were modest (~MeV), but prospects for improvement are offered through further tailoring the gas jet density profile. Also, we observed that this mechanism is very robust in producing those beams and thus can be considered as a future candidate in laser-driven ion sources driven by the upcoming next generation of multi-PW near-infrared lasers.

Published
2017

24. Imaging the noncentrosymmetric structural organization of tendon with Interferometric Second Harmonic Generation microscopy

Author

Rivard, M, Popov, K, Couture, CA, Laliberté, M, Bertrand-Grenier, A, Martin, F, Pépin, H, Pfeffer, CP, Brown, C, Ramunno, L, and Légaré, F

Subjects
macromolecular substances
Abstract

We report the imaging of tendon with Interferometric Second Harmonic Generation microscopy. We observe that the noncentrosymmetric structural organization can be maintained along the fibrillar axis over more than 150 μm, while in the transverse direction it is ∼1-15 μm. Those results are explained by modeling tendon as a heterogeneous distribution of noncentrosymmetric nano-cylinders (collagen fibrils) oriented along the fibrillar axis. The preservation of the noncentrosymmetric structural organization over multiple tens of microns reveals that tendon is made of domains in which the ratio between fibrils with positive and negative polarity is unbalanced.

Published
2016

25. Enhancement of Quasistationary Shocks and Heating via Temporal Staging in a Magnetized Laser-Plasma Jet

Author

Higginson, D. P., primary, Khiar, B., additional, Revet, G., additional, Béard, J., additional, Blecher, M., additional, Borghesi, M., additional, Burdonov, K., additional, Chen, S. N., additional, Filippov, E., additional, Khaghani, D., additional, Naughton, K., additional, Pépin, H., additional, Pikuz, S., additional, Portugall, O., additional, Riconda, C., additional, Riquier, R., additional, Rodriguez, R., additional, Ryazantsev, S. N., additional, Skobelev, I. Yu., additional, Soloviev, A., additional, Starodubtsev, M., additional, Vinci, T., additional, Willi, O., additional, Ciardi, A., additional, and Fuchs, J., additional

Published
2017
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26. Acceleration of collimated 45 MeV protons by collisionless shocks driven in low-density, large-scale gradient plasmas by a 1020 W/cm2, 1 µm laser

Author

Antici, P., primary, Boella, E., additional, Chen, S. N., additional, Andrews, D. S., additional, Barberio, M., additional, Böker, J., additional, Cardelli, F., additional, Feugeas, J. L., additional, Glesser, M., additional, Nicolaï, P., additional, Romagnani, L., additional, Scisciò, M., additional, Starodubtsev, M., additional, Willi, O., additional, Kieffer, J. C., additional, Tikhonchuk, V., additional, Pépin, H., additional, Silva, L. O., additional, Humières, E. d’, additional, and Fuchs, J., additional

Published
2017
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27. Laser plasma x-ray sources for microlithography.

Author

Chaker, M., Pépin, H., Bareau, V., Lafontaine, B., Toubhans, I., Fabbro, R., and Faral, B.

Subjects
*LASERS, *X-rays
Abstract

Focuses on a study that investigated both theoretically and experimentally the influence of the laser target parameters on the x-ray emission in different spectral ranges for two laser wavelengths. Experimental conditions; Outline of the theoretical model; Optimization of the x-ray emission.

Published
1988
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31. Effect of rapid thermal annealing on both the stress and the bonding states of a-SiC:H films.

Author

El Khakani, M. A., Chaker, M., Jean, A., Boily, S., Pépin, H., Kieffer, J. C., and Gujrathi, S. C.

Subjects
CHEMICAL vapor deposition, THIN films, SILICON carbide, ANNEALING of metals, PHOTOELECTRON spectroscopy
Abstract

Examines the stress evolution of plasma enhanced chemical vapor deposition hydrogenated amorphous silicon carbide films by increasing the annealing temperature. Preparation of the films; Infrared absorption analysis; Information on the X-ray photoelectron spectroscopy analysis.

Published
1993
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32. Characterization of a-SiC:H films produced in a standard plasma enhanced chemical vapor deposition system for x-ray mask application.

Author

Jean, A., Chaker, M., Diawara, Y., Leung, P. K., Gat, E., Mercier, P. P., Pépin, H., Gujrathi, S., Ross, G. G., and Kieffer, J. C.

Subjects
THIN films, SILICON, SILANE, METHANE, ARGON
Abstract

Presents a study which prepared hydrogenated amorphous a-Si[cubx]C[sub1-x]:H films with various compositions using a radio frequency glow discharge decomposition of a silane and methane mixture diluted in argon. Details on the deposition of the silicon carbide (SiC) film; Characterization of the films; Preparation and characterization of x-ray SiC membranes.

Published
1992
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38. Laboratory modeling of magnetized accretion dynamics

Author

Revet, G., Higginson, D. P., Béard, J., Bleicher, M., Burdonov, K., Borghesi, M., Chen, S. N., Khagani, D., Khiar, B., Naughton, K., Pikuz, S., Riconda, C., Riquier, R., Soloviev, A., Vinci, T., Willi, O., Portugall, O., Pépin, H., Andrea Ciardi, and Fuchs, J.

Subjects
Atomic and Molecular Physics, and Optics
Published
2015

39. Dynamics and structure of self-generated magnetics fields on solids following high contrast, high intensity laser irradiation

Author

Albertazzi, B., primary, Chen, S. N., additional, Antici, P., additional, Böker, J., additional, Borghesi, M., additional, Breil, J., additional, Dervieux, V., additional, Feugeas, J. L., additional, Lancia, L., additional, Nakatsutsumi, M., additional, Nicolaï, Ph., additional, Romagnagni, L., additional, Shepherd, R., additional, Sentoku, Y., additional, Starodubtsev, M., additional, Swantusch, M., additional, Tikhonchuk, V. T., additional, Willi, O., additional, d'Humières, E., additional, Pépin, H., additional, and Fuchs, J., additional

Published
2015
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40. Longitudinal laser ion acceleration in low density targets: experimental optimization on the Titan laser facility and numerical investigation of the ultra-high intensity limit

Author

d'Humières, E., additional, Chen, S., additional, Lobet, M., additional, Sciscio, M., additional, Antici, P., additional, Bailly-Grandvaux, M., additional, Gangolf, T., additional, Revet, G., additional, Santos, J., additional, Schroer, A.M., additional, Willi, O., additional, Tikhonchuk, V., additional, Pépin, H., additional, and Fuchs, J., additional

Published
2015
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41. A compact broadband ion beam focusing device based on laser-driven megagauss thermoelectric magnetic fields

Author

Albertazzi, B., primary, d’Humières, E., additional, Lancia, L., additional, Dervieux, V., additional, Antici, P., additional, Böcker, J., additional, Bonlie, J., additional, Breil, J., additional, Cauble, B., additional, Chen, S. N., additional, Feugeas, J. L., additional, Nakatsutsumi, M., additional, Nicolaï, P., additional, Romagnani, L., additional, Shepherd, R., additional, Sentoku, Y., additional, Swantusch, M., additional, Tikhonchuk, V. T., additional, Borghesi, M., additional, Willi, O., additional, Pépin, H., additional, and Fuchs, J., additional

Published
2015
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42. Dynamic compaction of high-temperature superconducting YBa2Cu3Ox powders by laser-driven shocks.

Author

Darquey, P., Kieffer, J. C., Gauthier, J., Pépin, H., Chaker, M., Champagne, B., Villeneuve, D., and Baldis, H.

Subjects
CERAMIC powders, SUPERCONDUCTORS, SHOCK waves
Abstract

Presents a study that used laser-driven shocks to densify high-temperature superconducting YBa[sub2]Cu[sub3]O[sub7] ceramic powders. Pros and cons of consolidating ceramic powders using explosively generated shock waves; Physical aspect of a YBaCuO compact after irradiation; Variation in the temperature of the intragrain and intergrain peaks.

Published
1991
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43. Topology of Megagauss Magnetic Fields and of Heat-Carrying Electrons Produced in a High-Power Laser-Solid Interaction

Author

Lancia, L., primary, Albertazzi, B., additional, Boniface, C., additional, Grisollet, A., additional, Riquier, R., additional, Chaland, F., additional, Le Thanh, K.-C., additional, Mellor, Ph., additional, Antici, P., additional, Buffechoux, S., additional, Chen, S. N., additional, Doria, D., additional, Nakatsutsumi, M., additional, Peth, C., additional, Swantusch, M., additional, Stardubtsev, M., additional, Palumbo, L., additional, Borghesi, M., additional, Willi, O., additional, Pépin, H., additional, and Fuchs, J., additional

Published
2014
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44. Production of large volume, strongly magnetized laser-produced plasmas by use of pulsed external magnetic fields

Author

Albertazzi, B., Béard, J., Ciardi, A., Vinci, T., Albrecht, J., Billette, J., Burris-Mog, T., Chen, S. N., Da Silva, D., Dittrich, S., Herrmannsdörfer, T., Hirardin, B., Kroll, F., Nakatsutsumi, M., Nitsche, S., Riconda, C., Romagnagni, L., Schlenvoigt, H.-P., Simond, S., Veuillot, E., Cowan, T. E., Portugall, O., Pépin, H., Fuchs, J., Albertazzi, B., Béard, J., Ciardi, A., Vinci, T., Albrecht, J., Billette, J., Burris-Mog, T., Chen, S. N., Da Silva, D., Dittrich, S., Herrmannsdörfer, T., Hirardin, B., Kroll, F., Nakatsutsumi, M., Nitsche, S., Riconda, C., Romagnagni, L., Schlenvoigt, H.-P., Simond, S., Veuillot, E., Cowan, T. E., Portugall, O., Pépin, H., and Fuchs, J.

Abstract

The production of strongly magnetized laser plasmas, of interest for laboratory astrophysics and inertial confinement fusion studies, is presented. This is achieved by coupling a 16 kV pulse-power system. This is achieved by coupling a 16 kV pulse-power system, which generates a magnetic field by means of a split coil, with the ELFIE laser facility at Ecole Polytechnique. In order to influence the plasma dynamics in a significant manner, the system can generate, repetitively and without debris, high amplitude magnetic fields (40 T) in a manner compatible with a high-energy laser environment. A description of the system and preliminary results demonstrating the possibility to magnetically collimate plasma jets are given.

Published
2013

46. Investigation of longitudinal proton acceleration in exploded targets irradiated by intense short-pulse laser

Author

Gauthier, M., primary, Lévy, A., additional, d'Humières, E., additional, Glesser, M., additional, Albertazzi, B., additional, Beaucourt, C., additional, Breil, J., additional, Chen, S. N., additional, Dervieux, V., additional, Feugeas, J. L., additional, Nicolaï, P., additional, Tikhonchuk, V., additional, Pépin, H., additional, Antici, P., additional, and Fuchs, J., additional

Published
2014
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47. Investigation of laser ion acceleration in low-density targets using exploded foils

Author

d'Humières, E, primary, Antici, P, additional, Glesser, M, additional, Boeker, J, additional, Cardelli, F, additional, Chen, S, additional, Feugeas, J L, additional, Filippi, F, additional, Gauthier, M, additional, Levy, A, additional, Nicolaï, P, additional, Pépin, H, additional, Romagnani, L, additional, Scisciò, M, additional, Tikhonchuk, V T, additional, Willi, O, additional, Kieffer, J C, additional, and Fuchs, J, additional

Published
2013
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49. Production of large volume, strongly magnetized laser-produced plasmas by use of pulsed external magnetic fields

Author

Albertazzi, B., primary, Béard, J., additional, Ciardi, A., additional, Vinci, T., additional, Albrecht, J., additional, Billette, J., additional, Burris-Mog, T., additional, Chen, S. N., additional, Da Silva, D., additional, Dittrich, S., additional, Herrmannsdörfer, T., additional, Hirardin, B., additional, Kroll, F., additional, Nakatsutsumi, M., additional, Nitsche, S., additional, Riconda, C., additional, Romagnagni, L., additional, Schlenvoigt, H.-P., additional, Simond, S., additional, Veuillot, E., additional, Cowan, T. E., additional, Portugall, O., additional, Pépin, H., additional, and Fuchs, J., additional

Published
2013
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