C. Riconda - Academia.edu (original) (raw)

Papers by C. Riconda

Research paper thumbnail of Evolution of the autoresonant plasma wave excitation in two-dimensional particle-in-cell simulations

arXiv (Cornell University), Jun 10, 2024

Research paper thumbnail of Electron acceleration by laser plasma wedge interaction

A new electron acceleration mechanism is identified that develops when a relativistically intense... more A new electron acceleration mechanism is identified that develops when a relativistically intense laser irradiates the wedge of an over-dense plasma. This induces a diffracted electromagnetic wave with a significant longitudinal electric field that accelerates electrons from the plasma over long distances to relativistic energies. Well collimated, highly-charged (nC) electron bunches with energies up to 100's MeV are obtained using a laser beam with Iλ 2 0 = 3.5 × 10 19 Wµm 2 /cm 2. Multidimensional particle-in-cell simulations, supported by a simple analytical model, confirm the efficiency and robustness of the proposed acceleration scheme.

Research paper thumbnail of Introduction à la physique des plasmas

International audienceLes plasmas sont peu présents dans notre environnement immédiat et leurs pr... more International audienceLes plasmas sont peu présents dans notre environnement immédiat et leurs propriétés sont parfois ignorées des physiciens. Il sagit pourtant de phénomènes universels quon rencontre depuis les décharges électriques jusquaux jets galactiques. Lobjectif de cet ouvrage est doffrir une introduction aux phénomènes variés qui constituent la physique des plasmas avec comme seul prérequis davoir une connaissance de la physique de base. Il présente en parallèle les fondements de la théorie des plasmas et un certain nombre dapplications aux plasmas de laboratoire ou aux plasmas naturels. Un accent particulier est mis sur lexistence des plasmas sans collision, dans lesquels le comportement collectif du milieu est dû seulement au champ électromagnétique moyen qui régit les trajectoires des particules. Ceci permet de porter un regard neuf sur des notions déjà abordées dans dautres disciplines, mais aussi de comprendre les liens qui existent entre les théories fluides, en part...

Research paper thumbnail of Introduction to plasma physics

Research paper thumbnail of Investigating strong-field QED processes in laser-electron beam collisions at Apollon

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of C © EDP Sciences, Les Ulis DOI: 10.1051/jp4:2006133053 Electromagnetic droplets created by stimulated Brillouin backscattering

Abstract. Recent particle-in-cell simulations of the stimulated Brillouin backscattering (SBBS) o... more Abstract. Recent particle-in-cell simulations of the stimulated Brillouin backscattering (SBBS) of electromagnetic radiation have shown that non-drifting solitary waves are easily produced even at sub-relativistic intensities (I2 = 1016Wm2/cm2), and remain almost unchanged all along the simulation time. The associated formation of strong density depressions disrupts the resonant SBBS amplification, enables strong electron and ion heating and leads to a final low-level saturated regime for the reflected radiation. In this paper, we review the main phases which characterize this regime of interaction, as resulting from the numerical simulations. A theoretical model of electromagnetic solitons in hot and dense plasmas is used to derive the physical characteristics of the resulting electromagnetic solitons and to compare these predictions with the numerical results. 1.

Research paper thumbnail of DOI: 10.1051/epjconf/20135905003 C © Owned by the authors, published by EDP Sciences, 2013 Laser plasma interaction physics on the LIL facility

Abstract. We present an overview of the interpretation of laser plasma interaction (LPI) experime... more Abstract. We present an overview of the interpretation of laser plasma interaction (LPI) experiments carried out on the LIL facility. These multikilojoule experiments have been done using underdense foam targets at 0.351 m laser light leading to high temperature and large plasmas. We discuss the interpretation using our different numerical tools: hydrodynamics simulations carried out with the code FCI2 to characterize the plasma, linear gain estimates with the postprocessor Piranah and paraxial simulations with the code HERA. 1.

Research paper thumbnail of Impact of the laser spatio-temporal shape on Breit–Wheeler pair production

New Journal of Physics, 2021

The forthcoming generation of multi-petawatt lasers opens the way to abundant pair production by ... more The forthcoming generation of multi-petawatt lasers opens the way to abundant pair production by the nonlinear Breit–Wheeler process, i.e. the decay of a photon into an electron–positron pair inside an intense laser field. In this paper we explore the optimal conditions for Breit–Wheeler pair production in the head-on collision of a laser pulse with gamma photons. The role of the laser peak intensity versus the focal spot size and shape is examined keeping a constant laser energy to match experimental constraints. A simple model for the soft-shower case, where most pairs originate from the decay of the initial gamma photons, is derived. This approach provides us with a semi-analytical model for more complex situations involving either Gaussian or Laguerre–Gauss (LG) laser beams. We then explore the influence of the order of the LG beams on pair creation. Finally we obtain the result that, above a given threshold, a larger spot size (or a higher order in the case of LG laser beams) i...

Research paper thumbnail of Nonlinear dynamics of laser-generated ion-plasma gratings: A unified description

Physical Review E, 2019

Laser-generated plasma gratings are dynamic optical elements for the manipulation of coherent lig... more Laser-generated plasma gratings are dynamic optical elements for the manipulation of coherent light at high intensities, beyond the damage threshold of solid-stated based materials. Their formation, evolution and final collapse require a detailed understanding. In this paper, we present a model to explain the nonlinear dynamics of high amplitude plasma gratings in the spatially periodic ponderomotive potential generated by two identical counter-propagating lasers. Both, fluid and kinetic aspects of the grating dynamics are analyzed. It is shown that the adiabatic electron compression plays a crucial role as the electron pressure may reflect the ions from the grating and induce the grating to break in an X-type manner. A single parameter is found to determine the behaviour of the grating and distinguish three fundamentally different regimes for the ion dynamics: completely reflecting, partially reflecting/partially passing, and crossing. Criteria for saturation and lifetime of the grating as well as the effect of finite ion temperature are presented.

Research paper thumbnail of Plasma optics in the context of high intensity lasers

Matter and Radiation at Extremes, 2019

The use of plasmas provides a way to overcome the low damage threshold of classical solid-state b... more The use of plasmas provides a way to overcome the low damage threshold of classical solid-state based optical materials, which is the main limitation encountered in producing and manipulating intense and energetic laser pulses. Plasmas can directly amplify or alter the characteristics of ultra-short laser pulses via the three-wave coupling equations for parametric processes. The strong-coupling regime of Brillouin scattering (sc-SBS) is of particular interest: recent progress in this domain is presented here. This includes the role of the global phase in the spatio-temporal evolution of the three-wave coupled equations for backscattering that allows a description of the coupling dynamics and the various stages of amplification from the initial growth to the so-called self-similar regime. The understanding of the phase evolution allows control of the directionality of the energy transfer via the phase relation between the pulses. A scheme that exploits this coupling in order to use the plasma as a wave plate is also suggested.

Research paper thumbnail of Raman–Brillouin interplay for inertial confinement fusion relevant laser–plasma interaction

High Power Laser Science and Engineering, 2016

The co-existence of the Raman and Brillouin backscattering instability is an important issue for ... more The co-existence of the Raman and Brillouin backscattering instability is an important issue for inertial confinement fusion. The present paper presents extensive one-dimensional (1D) particle-in-cell (PIC) simulations for a wide range of parameters extending and complementing previous findings. PIC simulations show that the scenario of reflectivity evolution and saturation is very sensitive to the temperatures, intensities, size of plasma and boundary conditions employed. The Langmuir decay instability is observed for rather small$k_{epw}{\it\lambda}_{D}$but has no influence on the saturation of Brillouin backscattering, although there is a clear correlation of Langmuir decay instability modes and ion-fractional decay for certain parameter ranges. Raman backscattering appears at any intensity and temperature but is only a transient phenomenon. In several configurations forward as well as backward Raman scattering is observed. For the intensities considered,$I{\it\lambda}_{o}^{2}$ab...

Research paper thumbnail of Excitation of Contained Modes by Energetic Particles

Research paper thumbnail of Roles of the Quadrupole Interaction and of the Quadratic Stark Effect in Spectral Lines from Plasmas Interacting with a Strong Quasimonochromatic Electric Field

We present an advanced analysis of the spectroscopic signatures of the interaction of a strong Qu... more We present an advanced analysis of the spectroscopic signatures of the interaction of a strong Quasimonochromatic Electric Field (QEF), generated by a high-power short-pulse laser, with a preformed laser-produced plasma. The computation of a synthetic spectrum emitted by such plasmas requires the calculation of the Stark line shape in the presence of a QEF and the evaluation of the QEF intensity profile throughout the line of sight in the plasma. Stark profiles in hot dense plasmas containing a strong QEF are calculated using the so-called Floquet-Liouville formalism. In this paper, in distinction to our previous publications, we studied the roles of the quadrupole interaction with the ion microfield and of the quadratic Stark effect. Then Particle-In-Cell (PIC) kinetic simulations were performed for taking into account the inhomogeneity of the QEF intensity. These theoretical calculations were applied for a spectroscopic analysis of the experimental Al He β line. The spectroscopic signatures of the QEF are prominent satellites, non-symmetrical with respect to the unperturbed line and distinguishable from the dielectronic satellites. We found that the allowance for the quadratic Stark effect was important for the consistent interpretation of the experimental results, while the allowance for the quadrupole interaction with the ion microfield did not play a significant role.

Research paper thumbnail of Temperature dependence of parametric instabilities in the context of the shock-ignition approach to inertial confinement fusion

High Power Laser Science and Engineering, 2015

The role of the coronal electron plasma temperature for shock-ignition conditions is analysed wit... more The role of the coronal electron plasma temperature for shock-ignition conditions is analysed with respect to the dominant parametric processes: stimulated Brillouin scattering, stimulated Raman scattering, two-plasmon decay (TPD), Langmuir decay instability (LDI) and cavitation. TPD instability and cavitation are sensitive to the electron temperature. At the same time the reflectivity and high-energy electron production are strongly affected. For low plasma temperatures the LDI plays a dominant role in the TPD saturation. An understanding of laser–plasma interaction in the context of shock ignition is an important issue due to the localization of energy deposition by collective effects and hot electron production. This in turn can have consequences for the compression phase and the resulting gain factor of the implosion phase.

Research paper thumbnail of Excitation of contained interacting modes by fusion products

IEEE Conference Record - Abstracts. 1996 IEEE International Conference on Plasma Science

ABSTRACT

Research paper thumbnail of Laser–plasma interaction experiments in the context of inertial fusion

Plasma Physics and Controlled Fusion, 2004

ABSTRACT

Research paper thumbnail of Spectral characteristics of ultra-short laser pulses in plasma amplifiers

Physics of Plasmas, 2013

ABSTRACT Amplification of laser pulses based on the backscattering process in plasmas can be perf... more ABSTRACT Amplification of laser pulses based on the backscattering process in plasmas can be performed using either the response of an electron plasma wave or an ion-acoustic wave. However, if the pulse durations become very short and the natural spread in frequency a substantial amount of the frequency itself, the Raman and Brillouin processes start to mix. Kinetic simulations show the transition from a pure amplification regime, in this case strong-coupling Brillouin, to a regime where a considerable downshift of the frequency of the amplified pulse takes place. It is conjectured that in the case of very short pulses, multi-modes are excited which contribute to the amplification process.

Research paper thumbnail of Strongly enhanced laser absorption and electron acceleration via resonant excitation of surface plasma waves

Physics of Plasmas, 2007

Two-dimensional ͑2D͒ particle-in-cell numerical simulations of the interaction between a high-int... more Two-dimensional ͑2D͒ particle-in-cell numerical simulations of the interaction between a high-intensity short-pulse p-polarized laser beam and an overdense plasma are presented. It is shown that, under appropriate physical conditions, a surface plasma wave can be resonantly excited by a short-pulse laser wave, leading to strong relativistic electron acceleration together with a dramatic increase, up to 70%, of light absorption by the plasma. Purely 2D effects contribute to enhancement of electron acceleration. It is also found that the angular distribution of the hot electrons is drastically affected by the surface wave. The subsequent ion dynamics is shown to be significantly modified by the surface plasma wave excitation.

Research paper thumbnail of Efficient laser-overdense plasma coupling via surface plasma waves and steady magnetic field generation

Physics of Plasmas, 2011

The efficiency of laser overdense plasma coupling via surface plasma wave excitation is investiga... more The efficiency of laser overdense plasma coupling via surface plasma wave excitation is investigated. Two-dimensional particle-in-cell simulations are performed over a wide range of laser pulse intensity from 10 15 to 10 20 W cm À2 lm 2 with electron density ranging from 25 to 100n c to describe the laser interaction with a grating target where a surface plasma wave excitation condition is fulfilled. The numerical studies confirm an efficient coupling with an enhancement of the laser absorption up to 75%. The simulations also show the presence of a localized, quasi-static magnetic field at the plasma surface. Two interaction regimes are identified for low (Ik 2 < 10 17 W cm À2 lm 2) and high (Ik 2 > 10 17 W cm À2 lm 2) laser pulse intensities. At "relativistic" laser intensity, steady magnetic fields as high as $580 MG lm/k 0 at 7 Â 10 19 W cm À2 lm 2 are obtained in the simulations.

Research paper thumbnail of Laser-plasma interaction physics in multi kilojoule experiments

Journal of Physics: Conference Series, 2010

... Andrews, Fife KY16 9ST, Scotland, UK 9 FNSPE, Czech Technical University in Prague, 115 19 Pr... more ... Andrews, Fife KY16 9ST, Scotland, UK 9 FNSPE, Czech Technical University in Prague, 115 19 Prague 1, Czech Republic E-mail: christine.labaune@polytechnique.fr Abstract. An experiment carried out on the LIL facility is presented. ...

Research paper thumbnail of Evolution of the autoresonant plasma wave excitation in two-dimensional particle-in-cell simulations

arXiv (Cornell University), Jun 10, 2024

Research paper thumbnail of Electron acceleration by laser plasma wedge interaction

A new electron acceleration mechanism is identified that develops when a relativistically intense... more A new electron acceleration mechanism is identified that develops when a relativistically intense laser irradiates the wedge of an over-dense plasma. This induces a diffracted electromagnetic wave with a significant longitudinal electric field that accelerates electrons from the plasma over long distances to relativistic energies. Well collimated, highly-charged (nC) electron bunches with energies up to 100's MeV are obtained using a laser beam with Iλ 2 0 = 3.5 × 10 19 Wµm 2 /cm 2. Multidimensional particle-in-cell simulations, supported by a simple analytical model, confirm the efficiency and robustness of the proposed acceleration scheme.

Research paper thumbnail of Introduction à la physique des plasmas

International audienceLes plasmas sont peu présents dans notre environnement immédiat et leurs pr... more International audienceLes plasmas sont peu présents dans notre environnement immédiat et leurs propriétés sont parfois ignorées des physiciens. Il sagit pourtant de phénomènes universels quon rencontre depuis les décharges électriques jusquaux jets galactiques. Lobjectif de cet ouvrage est doffrir une introduction aux phénomènes variés qui constituent la physique des plasmas avec comme seul prérequis davoir une connaissance de la physique de base. Il présente en parallèle les fondements de la théorie des plasmas et un certain nombre dapplications aux plasmas de laboratoire ou aux plasmas naturels. Un accent particulier est mis sur lexistence des plasmas sans collision, dans lesquels le comportement collectif du milieu est dû seulement au champ électromagnétique moyen qui régit les trajectoires des particules. Ceci permet de porter un regard neuf sur des notions déjà abordées dans dautres disciplines, mais aussi de comprendre les liens qui existent entre les théories fluides, en part...

Research paper thumbnail of Introduction to plasma physics

Research paper thumbnail of Investigating strong-field QED processes in laser-electron beam collisions at Apollon

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of C © EDP Sciences, Les Ulis DOI: 10.1051/jp4:2006133053 Electromagnetic droplets created by stimulated Brillouin backscattering

Abstract. Recent particle-in-cell simulations of the stimulated Brillouin backscattering (SBBS) o... more Abstract. Recent particle-in-cell simulations of the stimulated Brillouin backscattering (SBBS) of electromagnetic radiation have shown that non-drifting solitary waves are easily produced even at sub-relativistic intensities (I2 = 1016Wm2/cm2), and remain almost unchanged all along the simulation time. The associated formation of strong density depressions disrupts the resonant SBBS amplification, enables strong electron and ion heating and leads to a final low-level saturated regime for the reflected radiation. In this paper, we review the main phases which characterize this regime of interaction, as resulting from the numerical simulations. A theoretical model of electromagnetic solitons in hot and dense plasmas is used to derive the physical characteristics of the resulting electromagnetic solitons and to compare these predictions with the numerical results. 1.

Research paper thumbnail of DOI: 10.1051/epjconf/20135905003 C © Owned by the authors, published by EDP Sciences, 2013 Laser plasma interaction physics on the LIL facility

Abstract. We present an overview of the interpretation of laser plasma interaction (LPI) experime... more Abstract. We present an overview of the interpretation of laser plasma interaction (LPI) experiments carried out on the LIL facility. These multikilojoule experiments have been done using underdense foam targets at 0.351 m laser light leading to high temperature and large plasmas. We discuss the interpretation using our different numerical tools: hydrodynamics simulations carried out with the code FCI2 to characterize the plasma, linear gain estimates with the postprocessor Piranah and paraxial simulations with the code HERA. 1.

Research paper thumbnail of Impact of the laser spatio-temporal shape on Breit–Wheeler pair production

New Journal of Physics, 2021

The forthcoming generation of multi-petawatt lasers opens the way to abundant pair production by ... more The forthcoming generation of multi-petawatt lasers opens the way to abundant pair production by the nonlinear Breit–Wheeler process, i.e. the decay of a photon into an electron–positron pair inside an intense laser field. In this paper we explore the optimal conditions for Breit–Wheeler pair production in the head-on collision of a laser pulse with gamma photons. The role of the laser peak intensity versus the focal spot size and shape is examined keeping a constant laser energy to match experimental constraints. A simple model for the soft-shower case, where most pairs originate from the decay of the initial gamma photons, is derived. This approach provides us with a semi-analytical model for more complex situations involving either Gaussian or Laguerre–Gauss (LG) laser beams. We then explore the influence of the order of the LG beams on pair creation. Finally we obtain the result that, above a given threshold, a larger spot size (or a higher order in the case of LG laser beams) i...

Research paper thumbnail of Nonlinear dynamics of laser-generated ion-plasma gratings: A unified description

Physical Review E, 2019

Laser-generated plasma gratings are dynamic optical elements for the manipulation of coherent lig... more Laser-generated plasma gratings are dynamic optical elements for the manipulation of coherent light at high intensities, beyond the damage threshold of solid-stated based materials. Their formation, evolution and final collapse require a detailed understanding. In this paper, we present a model to explain the nonlinear dynamics of high amplitude plasma gratings in the spatially periodic ponderomotive potential generated by two identical counter-propagating lasers. Both, fluid and kinetic aspects of the grating dynamics are analyzed. It is shown that the adiabatic electron compression plays a crucial role as the electron pressure may reflect the ions from the grating and induce the grating to break in an X-type manner. A single parameter is found to determine the behaviour of the grating and distinguish three fundamentally different regimes for the ion dynamics: completely reflecting, partially reflecting/partially passing, and crossing. Criteria for saturation and lifetime of the grating as well as the effect of finite ion temperature are presented.

Research paper thumbnail of Plasma optics in the context of high intensity lasers

Matter and Radiation at Extremes, 2019

The use of plasmas provides a way to overcome the low damage threshold of classical solid-state b... more The use of plasmas provides a way to overcome the low damage threshold of classical solid-state based optical materials, which is the main limitation encountered in producing and manipulating intense and energetic laser pulses. Plasmas can directly amplify or alter the characteristics of ultra-short laser pulses via the three-wave coupling equations for parametric processes. The strong-coupling regime of Brillouin scattering (sc-SBS) is of particular interest: recent progress in this domain is presented here. This includes the role of the global phase in the spatio-temporal evolution of the three-wave coupled equations for backscattering that allows a description of the coupling dynamics and the various stages of amplification from the initial growth to the so-called self-similar regime. The understanding of the phase evolution allows control of the directionality of the energy transfer via the phase relation between the pulses. A scheme that exploits this coupling in order to use the plasma as a wave plate is also suggested.

Research paper thumbnail of Raman–Brillouin interplay for inertial confinement fusion relevant laser–plasma interaction

High Power Laser Science and Engineering, 2016

The co-existence of the Raman and Brillouin backscattering instability is an important issue for ... more The co-existence of the Raman and Brillouin backscattering instability is an important issue for inertial confinement fusion. The present paper presents extensive one-dimensional (1D) particle-in-cell (PIC) simulations for a wide range of parameters extending and complementing previous findings. PIC simulations show that the scenario of reflectivity evolution and saturation is very sensitive to the temperatures, intensities, size of plasma and boundary conditions employed. The Langmuir decay instability is observed for rather small$k_{epw}{\it\lambda}_{D}$but has no influence on the saturation of Brillouin backscattering, although there is a clear correlation of Langmuir decay instability modes and ion-fractional decay for certain parameter ranges. Raman backscattering appears at any intensity and temperature but is only a transient phenomenon. In several configurations forward as well as backward Raman scattering is observed. For the intensities considered,$I{\it\lambda}_{o}^{2}$ab...

Research paper thumbnail of Excitation of Contained Modes by Energetic Particles

Research paper thumbnail of Roles of the Quadrupole Interaction and of the Quadratic Stark Effect in Spectral Lines from Plasmas Interacting with a Strong Quasimonochromatic Electric Field

We present an advanced analysis of the spectroscopic signatures of the interaction of a strong Qu... more We present an advanced analysis of the spectroscopic signatures of the interaction of a strong Quasimonochromatic Electric Field (QEF), generated by a high-power short-pulse laser, with a preformed laser-produced plasma. The computation of a synthetic spectrum emitted by such plasmas requires the calculation of the Stark line shape in the presence of a QEF and the evaluation of the QEF intensity profile throughout the line of sight in the plasma. Stark profiles in hot dense plasmas containing a strong QEF are calculated using the so-called Floquet-Liouville formalism. In this paper, in distinction to our previous publications, we studied the roles of the quadrupole interaction with the ion microfield and of the quadratic Stark effect. Then Particle-In-Cell (PIC) kinetic simulations were performed for taking into account the inhomogeneity of the QEF intensity. These theoretical calculations were applied for a spectroscopic analysis of the experimental Al He β line. The spectroscopic signatures of the QEF are prominent satellites, non-symmetrical with respect to the unperturbed line and distinguishable from the dielectronic satellites. We found that the allowance for the quadratic Stark effect was important for the consistent interpretation of the experimental results, while the allowance for the quadrupole interaction with the ion microfield did not play a significant role.

Research paper thumbnail of Temperature dependence of parametric instabilities in the context of the shock-ignition approach to inertial confinement fusion

High Power Laser Science and Engineering, 2015

The role of the coronal electron plasma temperature for shock-ignition conditions is analysed wit... more The role of the coronal electron plasma temperature for shock-ignition conditions is analysed with respect to the dominant parametric processes: stimulated Brillouin scattering, stimulated Raman scattering, two-plasmon decay (TPD), Langmuir decay instability (LDI) and cavitation. TPD instability and cavitation are sensitive to the electron temperature. At the same time the reflectivity and high-energy electron production are strongly affected. For low plasma temperatures the LDI plays a dominant role in the TPD saturation. An understanding of laser–plasma interaction in the context of shock ignition is an important issue due to the localization of energy deposition by collective effects and hot electron production. This in turn can have consequences for the compression phase and the resulting gain factor of the implosion phase.

Research paper thumbnail of Excitation of contained interacting modes by fusion products

IEEE Conference Record - Abstracts. 1996 IEEE International Conference on Plasma Science

ABSTRACT

Research paper thumbnail of Laser–plasma interaction experiments in the context of inertial fusion

Plasma Physics and Controlled Fusion, 2004

ABSTRACT

Research paper thumbnail of Spectral characteristics of ultra-short laser pulses in plasma amplifiers

Physics of Plasmas, 2013

ABSTRACT Amplification of laser pulses based on the backscattering process in plasmas can be perf... more ABSTRACT Amplification of laser pulses based on the backscattering process in plasmas can be performed using either the response of an electron plasma wave or an ion-acoustic wave. However, if the pulse durations become very short and the natural spread in frequency a substantial amount of the frequency itself, the Raman and Brillouin processes start to mix. Kinetic simulations show the transition from a pure amplification regime, in this case strong-coupling Brillouin, to a regime where a considerable downshift of the frequency of the amplified pulse takes place. It is conjectured that in the case of very short pulses, multi-modes are excited which contribute to the amplification process.

Research paper thumbnail of Strongly enhanced laser absorption and electron acceleration via resonant excitation of surface plasma waves

Physics of Plasmas, 2007

Two-dimensional ͑2D͒ particle-in-cell numerical simulations of the interaction between a high-int... more Two-dimensional ͑2D͒ particle-in-cell numerical simulations of the interaction between a high-intensity short-pulse p-polarized laser beam and an overdense plasma are presented. It is shown that, under appropriate physical conditions, a surface plasma wave can be resonantly excited by a short-pulse laser wave, leading to strong relativistic electron acceleration together with a dramatic increase, up to 70%, of light absorption by the plasma. Purely 2D effects contribute to enhancement of electron acceleration. It is also found that the angular distribution of the hot electrons is drastically affected by the surface wave. The subsequent ion dynamics is shown to be significantly modified by the surface plasma wave excitation.

Research paper thumbnail of Efficient laser-overdense plasma coupling via surface plasma waves and steady magnetic field generation

Physics of Plasmas, 2011

The efficiency of laser overdense plasma coupling via surface plasma wave excitation is investiga... more The efficiency of laser overdense plasma coupling via surface plasma wave excitation is investigated. Two-dimensional particle-in-cell simulations are performed over a wide range of laser pulse intensity from 10 15 to 10 20 W cm À2 lm 2 with electron density ranging from 25 to 100n c to describe the laser interaction with a grating target where a surface plasma wave excitation condition is fulfilled. The numerical studies confirm an efficient coupling with an enhancement of the laser absorption up to 75%. The simulations also show the presence of a localized, quasi-static magnetic field at the plasma surface. Two interaction regimes are identified for low (Ik 2 < 10 17 W cm À2 lm 2) and high (Ik 2 > 10 17 W cm À2 lm 2) laser pulse intensities. At "relativistic" laser intensity, steady magnetic fields as high as $580 MG lm/k 0 at 7 Â 10 19 W cm À2 lm 2 are obtained in the simulations.

Research paper thumbnail of Laser-plasma interaction physics in multi kilojoule experiments

Journal of Physics: Conference Series, 2010

... Andrews, Fife KY16 9ST, Scotland, UK 9 FNSPE, Czech Technical University in Prague, 115 19 Pr... more ... Andrews, Fife KY16 9ST, Scotland, UK 9 FNSPE, Czech Technical University in Prague, 115 19 Prague 1, Czech Republic E-mail: christine.labaune@polytechnique.fr Abstract. An experiment carried out on the LIL facility is presented. ...