Remi Capdessus - Academia.edu (original) (raw)

Papers by Remi Capdessus

This data corresponds to the simulation results reported in the publication "High-density el... more This data corresponds to the simulation results reported in the publication "High-density electron-ion bunch formation and multi-GeV positron production via radiative trapping in extreme-intensity laser-plasma interactions". Simulation data was generated by running EPOCH version 4.8.3 with the input.deck files included. Provisional data embargo until 10/10/20

The radiation pressure of next generation high-intensity lasers could efficiently accelerate ions... more The radiation pressure of next generation high-intensity lasers could efficiently accelerate ions to GeV energies. However, nonlinear quantum-electrodynamic effects play an important role in the interaction of these lasers with matter. We show that these quantum-electrodynamic effects lead to the production of a critical density pair-plasma which completely absorbs the laser pulse and consequently reduces the accelerated ion energy and efficiency by 30-50%.

New Journal of Physics, 2020

Multi-petawatt laser systems will open up a novel interaction regime mixing collective plasma and... more Multi-petawatt laser systems will open up a novel interaction regime mixing collective plasma and quantum electrodynamic processes, giving rise to prolific generation of gamma-ray photons and electron–positron pairs. Here, using particle-in-cell simulations, we investigate the physics of the interaction of a 1024 W cm−2 intensity, 30 fs duration, circularly polarized laser pulse with a long deuterium plasma at classically overcritical electron density (1022 cm−3). We show that radiative trapping of the plasma electrons causes a high-density (∼5 × 1023 cm−3), quasineutral electron–ion bunch to form inside the laser pulse. This phenomenon is accompanied by up to ∼40% energy conversion efficiency of the laser into gamma rays. Moreover, we find that both the radiation-modified Laplace force and the longitudinal electric field exerted on the positrons created by the multiphoton Breit–Wheeler process can accelerate them to GeV-range energies. We develop a theoretical model, the prediction...

Plasma Physics and Controlled Fusion, 2018

Physics of Plasmas, 2014

A new source of radiation can be created with a laser pulse of intensity %10 23 W/cm 2 interactin... more A new source of radiation can be created with a laser pulse of intensity %10 23 W/cm 2 interacting with a slightly overdense plasma. Collective effects driven by the electrostatic field significantly enhance the synchrotron radiation. They impact on the laser energy repartition leading to a specific emission but also constitute a crucial element for the intense radiation production. They allow electrons to be accelerated over a length up to 10 laser wavelengths favoring emission of an intense radiation. It is shown that charge separation field depends on the ion mass and target thickness but also on laser polarization. These phenomena are studied with an one dimensional relativistic particle-in-cell code accounting for the classical radiation reaction force.

EPJ Web of Conferences, 2013

Radiation losses of charged particles can become important in ultra high intensity laser plasma i... more Radiation losses of charged particles can become important in ultra high intensity laser plasma interaction. This process is described by the radiation back reaction term in the electron equation of motion. This term is implemented in the relativistic particle-in-cell code by using a renormalized Lorentz-Abraham-Dirac model. In the hole boring regime case of laser ion acceleration it is shown that radiation losses results in a decrease of the piston velocity.

The attached data corresponds to the simulation results included in the article "Relativisti... more The attached data corresponds to the simulation results included in the article "Relativistic Doppler-boosted gamma-rays in High Fields". The dataset comprises of 9 files of simulation data created using EPOCH version 4.8.3.

Physics of Plasmas, 2016

A radiating electron source is shown to be created by a laser pulse (with intensity of 10 23 W/cm... more A radiating electron source is shown to be created by a laser pulse (with intensity of 10 23 W/cm 2 and duration equal to 30 fs) interacting with a near-critical density plasma. It is shown that the back radiation reaction resulting from high energy synchrotron radiation tends to counteract the action of the ponderomotive force. This enhances the collective dynamics of the radiating electrons in the highest field areas, resulting in the production of a compact radiation source (containing 80% of the synchrotron radiation emission), with an energy on the order of tens of MeV over the laser pulse duration. These phenomena are investigated using a QED-particle-in-cell code, and compared with a kinetic model accounting for the radiation reaction force in the electron distribution function. The results shed new light on electron-photon sources at ultra-high laser intensities and could be tested on future laser facilities.

Plasma Physics and Controlled Fusion

Applied Sciences

The dynamics of the plasma critical density surface in an ultra-thin foil target irradiated by an... more The dynamics of the plasma critical density surface in an ultra-thin foil target irradiated by an ultra-intense (∼6 × 10 20 Wcm −2) laser pulse is investigated experimentally and via 2D particle-in-cell simulations. Changes to the surface motion are diagnosed as a function of foil thickness. The experimental and numerical results are compared with hole-boring and light-sail models of radiation pressure acceleration, to identify the foil thickness range for which each model accounts for the measured surface motion. Both the experimental and numerical results show that the onset of relativistic self-induced transparency, in the thinnest targets investigated, limits the velocity of the critical surface, and thus the effectiveness of radiation pressure acceleration.

Research Using Extreme Light: Entering New Frontiers with Petawatt-Class Lasers III

This is a repository copy of Ion acceleration with radiation pressure in quantum electrodynamic r... more This is a repository copy of Ion acceleration with radiation pressure in quantum electrodynamic regimes.

Physical Review D, 2016

Radiation reaction remains one of the most fascinating open questions in electrodynamics. The dev... more Radiation reaction remains one of the most fascinating open questions in electrodynamics. The development of multi-petawatt laser facilities capable of reaching extreme intensities has leant this topic a new urgency, and it is now more important than ever to properly understand it. Two models of radiation reaction, due to Landau and Lifshitz and to Sokolov, have gained prominence, but there has been little work exploring the relation between the two. We show that in the Sokolov theory electromagnetic fields induce a Lorentz transformation between momentum and velocity, which eliminates some of the counterintuitive results of Landau-Lifshitz. In particular, the Lorentz boost in a constant electric field causes the particle to lose electrostatic potential energy more rapidly than it otherwise would, explaining the long-standing mystery of how an electron can radiate while experience no radiation reaction force. These ideas are illustrated in examples of relevance to astrophysics and laser-particle interactions, where radiation reaction effects are particularly prominent.

Nature Physics, 2016

The collective response of charged particles to intense fields is intrinsic to plasma accelerator... more The collective response of charged particles to intense fields is intrinsic to plasma accelerators and radiation sources, relativistic optics and many astrophysical phenomena. Here we show that the fundamental optical process of diffraction occurs via the generation of a relativistic plasma aperture in thin foils undergoing relativistic induced transparency. The plasma electrons collectively respond to the resulting near-field diffraction pattern, producing a beam of energetic electrons with spatial structure which can be controlled by variation of the laser polarization, wavelength and focused intensity profile. The concept is demonstrated numerically and verified experimentally. The results provide new understanding of the formation of current structures in the relativistically transparent regime of laser-plasma interactions and is a viable step towards optical control of charged particle dynamics in laser-driven sources.

High-Power, High-Energy, and High-Intensity Laser Technology; and Research Using Extreme Light: Entering New Frontiers with Petawatt-Class Lasers, 2013

ABSTRACT We consider interaction of two counter-propagating homogeneous sub-relativistic plasma b... more ABSTRACT We consider interaction of two counter-propagating homogeneous sub-relativistic plasma beams with no external magnetic field applied. In numerical simulations performed with a particle-in-cell code three stages of evolution can be identified. The shock formation is initiated with development of the electron two stream and Weibel-like micro-instabilities, followed by fast electron heating and ion deceleration and heating. We present a theoretical analysis of the instabilities development and the nonlinear saturation to explore the origins of the heating and the magnetic field generation. From the dispersion relation, the instabilities are characterized and the dependence on the electron temperature and ion velocity is studied. The growth rate and the characteristic scales of instability are compared to simulation results.

High-Power, High-Energy, and High-Intensity Laser Technology; and Research Using Extreme Light: Entering New Frontiers with Petawatt-Class Lasers, 2013

ABSTRACT

EPJ Web of Conferences, 2013

Ion stream instabilities are essential for collisionless shock formation as seen in astrophysics.... more Ion stream instabilities are essential for collisionless shock formation as seen in astrophysics. Weakly relativistic shocks are considered as candidates for sources of high energy cosmic rays. Laboratory experiments may provide a better understanding of this phenomenon. High intensity short pulse laser systems are opening possibilities for efficient ion acceleration to high energies. Their collision with a secondary target could be used for collisionless shock formation. In this paper, using particle-in-cell simulations we are studying interaction of a sub-relativistic, laser created proton beam with a secondary gas target. We show that the ion bunch initiates strong electron heating accompanied by the Weibel-like filamentation and ion energy losses. The energy repartition between ions, electrons and magnetic fields are investigated. This yields insight on the processes occurring in the interstellar medium (ISM) and gamma-ray burst afterglows.

Physical Review E, 2015

The role of the radiation reaction force in ultraintense laser-driven ion acceleration is investi... more The role of the radiation reaction force in ultraintense laser-driven ion acceleration is investigated. For laser intensities ∼10 23 W/cm 2 , the action of this force on electrons is demonstrated in relativistic particle-in-cell simulations to significantly enhance the energy transfer to ions in relativistically transparent targets, but strongly reduce the ion energy in dense plasma targets. An expression is derived for the revised piston velocity, and hence ion energy, taking account of energy loses to synchrotron radiation generated by electrons accelerated in the laser field. Ion mass is demonstrated to be important by comparing results obtained with proton and deuteron plasma. The results can be verified in experiments with cryogenic hydrogen and deuterium targets.

EPJ Web of Conferences, 2013

New laser facilities able to deliver either ultra high energy short pulses or ultra high intensit... more New laser facilities able to deliver either ultra high energy short pulses or ultra high intensity pulses are being constructed and will open new and exciting opportunities for laser ion acceleration. The interaction of a high intensity short pulse with underdense, near-critical and overdense targets has been studied using 2D Particle-In-Cell simulations in these regimes. In the ultra high energy regime, proton beams with maximum energies of hundreds of MeV and a high number of high energy protons could be accelerated using thin solid foils or low density targets. In the ultra high intensity regime, radiation losses will start affecting laser ion acceleration using thin overdense targets for intensities higher than 10 22 W/cm 2 , and produce very energetic ions.

Plasma Physics and Controlled Fusion, 2012

Laser hole boring is a process of ion expulsion from the path of an intense laser beam under the ... more Laser hole boring is a process of ion expulsion from the path of an intense laser beam under the effect of the ponderomotive force. It is considered as a method for more efficient electron energy deposition in fast ignition of inertial fusion reactions. Analysis of the electron dynamics on the laser–plasma interface shows that the hole boring efficiency can be significantly enhanced by an appropriate temporal shaping of the laser pulse. The pulse shape optimization is carried out with a newly developed fast quasi-neutral particle-in-cell (PIC) code and verified with the full PIC simulations.

This data corresponds to the simulation results reported in the publication "High-density el... more This data corresponds to the simulation results reported in the publication "High-density electron-ion bunch formation and multi-GeV positron production via radiative trapping in extreme-intensity laser-plasma interactions". Simulation data was generated by running EPOCH version 4.8.3 with the input.deck files included. Provisional data embargo until 10/10/20

The radiation pressure of next generation high-intensity lasers could efficiently accelerate ions... more The radiation pressure of next generation high-intensity lasers could efficiently accelerate ions to GeV energies. However, nonlinear quantum-electrodynamic effects play an important role in the interaction of these lasers with matter. We show that these quantum-electrodynamic effects lead to the production of a critical density pair-plasma which completely absorbs the laser pulse and consequently reduces the accelerated ion energy and efficiency by 30-50%.

New Journal of Physics, 2020

Multi-petawatt laser systems will open up a novel interaction regime mixing collective plasma and... more Multi-petawatt laser systems will open up a novel interaction regime mixing collective plasma and quantum electrodynamic processes, giving rise to prolific generation of gamma-ray photons and electron–positron pairs. Here, using particle-in-cell simulations, we investigate the physics of the interaction of a 1024 W cm−2 intensity, 30 fs duration, circularly polarized laser pulse with a long deuterium plasma at classically overcritical electron density (1022 cm−3). We show that radiative trapping of the plasma electrons causes a high-density (∼5 × 1023 cm−3), quasineutral electron–ion bunch to form inside the laser pulse. This phenomenon is accompanied by up to ∼40% energy conversion efficiency of the laser into gamma rays. Moreover, we find that both the radiation-modified Laplace force and the longitudinal electric field exerted on the positrons created by the multiphoton Breit–Wheeler process can accelerate them to GeV-range energies. We develop a theoretical model, the prediction...

Plasma Physics and Controlled Fusion, 2018

Physics of Plasmas, 2014

A new source of radiation can be created with a laser pulse of intensity %10 23 W/cm 2 interactin... more A new source of radiation can be created with a laser pulse of intensity %10 23 W/cm 2 interacting with a slightly overdense plasma. Collective effects driven by the electrostatic field significantly enhance the synchrotron radiation. They impact on the laser energy repartition leading to a specific emission but also constitute a crucial element for the intense radiation production. They allow electrons to be accelerated over a length up to 10 laser wavelengths favoring emission of an intense radiation. It is shown that charge separation field depends on the ion mass and target thickness but also on laser polarization. These phenomena are studied with an one dimensional relativistic particle-in-cell code accounting for the classical radiation reaction force.

EPJ Web of Conferences, 2013

Radiation losses of charged particles can become important in ultra high intensity laser plasma i... more Radiation losses of charged particles can become important in ultra high intensity laser plasma interaction. This process is described by the radiation back reaction term in the electron equation of motion. This term is implemented in the relativistic particle-in-cell code by using a renormalized Lorentz-Abraham-Dirac model. In the hole boring regime case of laser ion acceleration it is shown that radiation losses results in a decrease of the piston velocity.

The attached data corresponds to the simulation results included in the article "Relativisti... more The attached data corresponds to the simulation results included in the article "Relativistic Doppler-boosted gamma-rays in High Fields". The dataset comprises of 9 files of simulation data created using EPOCH version 4.8.3.

Physics of Plasmas, 2016

A radiating electron source is shown to be created by a laser pulse (with intensity of 10 23 W/cm... more A radiating electron source is shown to be created by a laser pulse (with intensity of 10 23 W/cm 2 and duration equal to 30 fs) interacting with a near-critical density plasma. It is shown that the back radiation reaction resulting from high energy synchrotron radiation tends to counteract the action of the ponderomotive force. This enhances the collective dynamics of the radiating electrons in the highest field areas, resulting in the production of a compact radiation source (containing 80% of the synchrotron radiation emission), with an energy on the order of tens of MeV over the laser pulse duration. These phenomena are investigated using a QED-particle-in-cell code, and compared with a kinetic model accounting for the radiation reaction force in the electron distribution function. The results shed new light on electron-photon sources at ultra-high laser intensities and could be tested on future laser facilities.

Plasma Physics and Controlled Fusion

Applied Sciences

The dynamics of the plasma critical density surface in an ultra-thin foil target irradiated by an... more The dynamics of the plasma critical density surface in an ultra-thin foil target irradiated by an ultra-intense (∼6 × 10 20 Wcm −2) laser pulse is investigated experimentally and via 2D particle-in-cell simulations. Changes to the surface motion are diagnosed as a function of foil thickness. The experimental and numerical results are compared with hole-boring and light-sail models of radiation pressure acceleration, to identify the foil thickness range for which each model accounts for the measured surface motion. Both the experimental and numerical results show that the onset of relativistic self-induced transparency, in the thinnest targets investigated, limits the velocity of the critical surface, and thus the effectiveness of radiation pressure acceleration.

Research Using Extreme Light: Entering New Frontiers with Petawatt-Class Lasers III

This is a repository copy of Ion acceleration with radiation pressure in quantum electrodynamic r... more This is a repository copy of Ion acceleration with radiation pressure in quantum electrodynamic regimes.

Physical Review D, 2016

Radiation reaction remains one of the most fascinating open questions in electrodynamics. The dev... more Radiation reaction remains one of the most fascinating open questions in electrodynamics. The development of multi-petawatt laser facilities capable of reaching extreme intensities has leant this topic a new urgency, and it is now more important than ever to properly understand it. Two models of radiation reaction, due to Landau and Lifshitz and to Sokolov, have gained prominence, but there has been little work exploring the relation between the two. We show that in the Sokolov theory electromagnetic fields induce a Lorentz transformation between momentum and velocity, which eliminates some of the counterintuitive results of Landau-Lifshitz. In particular, the Lorentz boost in a constant electric field causes the particle to lose electrostatic potential energy more rapidly than it otherwise would, explaining the long-standing mystery of how an electron can radiate while experience no radiation reaction force. These ideas are illustrated in examples of relevance to astrophysics and laser-particle interactions, where radiation reaction effects are particularly prominent.

Nature Physics, 2016

The collective response of charged particles to intense fields is intrinsic to plasma accelerator... more The collective response of charged particles to intense fields is intrinsic to plasma accelerators and radiation sources, relativistic optics and many astrophysical phenomena. Here we show that the fundamental optical process of diffraction occurs via the generation of a relativistic plasma aperture in thin foils undergoing relativistic induced transparency. The plasma electrons collectively respond to the resulting near-field diffraction pattern, producing a beam of energetic electrons with spatial structure which can be controlled by variation of the laser polarization, wavelength and focused intensity profile. The concept is demonstrated numerically and verified experimentally. The results provide new understanding of the formation of current structures in the relativistically transparent regime of laser-plasma interactions and is a viable step towards optical control of charged particle dynamics in laser-driven sources.

High-Power, High-Energy, and High-Intensity Laser Technology; and Research Using Extreme Light: Entering New Frontiers with Petawatt-Class Lasers, 2013

ABSTRACT We consider interaction of two counter-propagating homogeneous sub-relativistic plasma b... more ABSTRACT We consider interaction of two counter-propagating homogeneous sub-relativistic plasma beams with no external magnetic field applied. In numerical simulations performed with a particle-in-cell code three stages of evolution can be identified. The shock formation is initiated with development of the electron two stream and Weibel-like micro-instabilities, followed by fast electron heating and ion deceleration and heating. We present a theoretical analysis of the instabilities development and the nonlinear saturation to explore the origins of the heating and the magnetic field generation. From the dispersion relation, the instabilities are characterized and the dependence on the electron temperature and ion velocity is studied. The growth rate and the characteristic scales of instability are compared to simulation results.

High-Power, High-Energy, and High-Intensity Laser Technology; and Research Using Extreme Light: Entering New Frontiers with Petawatt-Class Lasers, 2013

ABSTRACT

EPJ Web of Conferences, 2013

Ion stream instabilities are essential for collisionless shock formation as seen in astrophysics.... more Ion stream instabilities are essential for collisionless shock formation as seen in astrophysics. Weakly relativistic shocks are considered as candidates for sources of high energy cosmic rays. Laboratory experiments may provide a better understanding of this phenomenon. High intensity short pulse laser systems are opening possibilities for efficient ion acceleration to high energies. Their collision with a secondary target could be used for collisionless shock formation. In this paper, using particle-in-cell simulations we are studying interaction of a sub-relativistic, laser created proton beam with a secondary gas target. We show that the ion bunch initiates strong electron heating accompanied by the Weibel-like filamentation and ion energy losses. The energy repartition between ions, electrons and magnetic fields are investigated. This yields insight on the processes occurring in the interstellar medium (ISM) and gamma-ray burst afterglows.

Physical Review E, 2015

The role of the radiation reaction force in ultraintense laser-driven ion acceleration is investi... more The role of the radiation reaction force in ultraintense laser-driven ion acceleration is investigated. For laser intensities ∼10 23 W/cm 2 , the action of this force on electrons is demonstrated in relativistic particle-in-cell simulations to significantly enhance the energy transfer to ions in relativistically transparent targets, but strongly reduce the ion energy in dense plasma targets. An expression is derived for the revised piston velocity, and hence ion energy, taking account of energy loses to synchrotron radiation generated by electrons accelerated in the laser field. Ion mass is demonstrated to be important by comparing results obtained with proton and deuteron plasma. The results can be verified in experiments with cryogenic hydrogen and deuterium targets.

EPJ Web of Conferences, 2013

New laser facilities able to deliver either ultra high energy short pulses or ultra high intensit... more New laser facilities able to deliver either ultra high energy short pulses or ultra high intensity pulses are being constructed and will open new and exciting opportunities for laser ion acceleration. The interaction of a high intensity short pulse with underdense, near-critical and overdense targets has been studied using 2D Particle-In-Cell simulations in these regimes. In the ultra high energy regime, proton beams with maximum energies of hundreds of MeV and a high number of high energy protons could be accelerated using thin solid foils or low density targets. In the ultra high intensity regime, radiation losses will start affecting laser ion acceleration using thin overdense targets for intensities higher than 10 22 W/cm 2 , and produce very energetic ions.

Plasma Physics and Controlled Fusion, 2012

Laser hole boring is a process of ion expulsion from the path of an intense laser beam under the ... more Laser hole boring is a process of ion expulsion from the path of an intense laser beam under the effect of the ponderomotive force. It is considered as a method for more efficient electron energy deposition in fast ignition of inertial fusion reactions. Analysis of the electron dynamics on the laser–plasma interface shows that the hole boring efficiency can be significantly enhanced by an appropriate temporal shaping of the laser pulse. The pulse shape optimization is carried out with a newly developed fast quasi-neutral particle-in-cell (PIC) code and verified with the full PIC simulations.