ABSTRACT An integral back-transform has been developed to retrieve the polar magnetic component i... more ABSTRACT An integral back-transform has been developed to retrieve the polar magnetic component in a cylindrically symmetric plasma from a single projection. The formula is derived from parallel forward Radon transform (Abel transform) of a source-free vector field. Two numerical schemes are proposed to solve the backward transform. These schemes have been tested successfully with predefined plasma parameters. The practical application to the analysis of experimental Faraday rotation measurements is also presented, leading to the reconstruction of the transverse profile of the magnetic field.
Experimental and theoretical results on the stimulated Raman backscattering (SRS) reflectivity of... more Experimental and theoretical results on the stimulated Raman backscattering (SRS) reflectivity of a short laser pulse (120 fs) interaction with an optically ionized helium gas are presented. The reflectivity is measured as a function of the gas pressure from 1 to 100 Torr. A monodimensional (1-D) theoretical model, including the refraction induced during the ionization process, describes the dependence of
The all optical external injection scheme that we will use with two colliding laser pulses allows... more The all optical external injection scheme that we will use with two colliding laser pulses allows a way to stabilize the injection of electrons into the plasma wave, and to easily tune the energy of the output beam by changing the longitudinal position of the injection. The charge and relative energy spread are also controllable by tuning parameters such as the injection intensity and its polarization. We report here on the control of the e-beam parameters, on the e-beam parameters that will be used for the conception and design of the emittance meter and on the experimental arrangement on which emittance measurement experiments will be achieved.
ABSTRACT We demonstrate the generation of high quality electron beams resulting from the interact... more ABSTRACT We demonstrate the generation of high quality electron beams resulting from the interaction of ultrashort and ultraintense laser pulses with underdense plasmas. The electron energy distribution is quasi-monoenergetic and peaks at 170 MeV
Laser Acceleration of Electrons, Protons, and Ions II; and Medical Applications of Laser-Generated Beams of Particles II; and Harnessing Relativistic Plasma Waves III, 2013
ABSTRACT We report on an experimental demonstration of laser wake field electron acceleration usi... more ABSTRACT We report on an experimental demonstration of laser wake field electron acceleration using few-milijoule laser pulses tightly focused on a 100 μm scale gas target. Using a comparatively low energy pulse has the benefit of a more compact system with a high repetition rate (typically kHz), which can prove useful for both practical applications and better statistical studies of laser plasma interactions. A proof-of-principle experiment was conducted to demonstrate the applicability of such electron sources from laser plasma wake field accelerator for ultrafast electron diffraction.
... Focusing a laser pulse with a spherical or an axial lens onto the edge of the gas ... The bac... more ... Focusing a laser pulse with a spherical or an axial lens onto the edge of the gas ... The backing pressure is also limited, as the installation of an additional pump complicates the ... The resultingjet should be stable and quasistationary to simplify the synchronization of the valve and ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2011
... Permissions & Reprints. Optimization of gamma-ray beams produced by a laser-plasma accele... more ... Permissions & Reprints. Optimization of gamma-ray beams produced by a laser-plasma accelerator. A. Ben-Ismaïl a , b , Corresponding Author Contact Information , E-mail The Corresponding Author , J. Faure a and V. Malka a. ...
It is known that relativistic laser plasma interactions can already today induce accelerating fie... more It is known that relativistic laser plasma interactions can already today induce accelerating fields beyond some TV/m, which are indeed capable to efficiently accelerate plasma background electrons as well as protons. An introduction to the current state of the art will be given and possible applications of these optically induced charged particle sources will be discussed.
Stable and high quality electron beams are produced when two laser pulses collide in underdense p... more Stable and high quality electron beams are produced when two laser pulses collide in underdense plasmas. In addition to the improvement of the stability of the electron beam, the use of a second laser pulse allows the control of the electron beam parameters (energy, relative energy spread, and charge). The experimental features are well explained by the use of PIC simulations which underline physics processes which were not predicted by fluid model. This control is obtained by changing laser pulse energy, laser pulses polarization or electron density. With a total of 1 J laser energy, a 10 pC electron beam at 200 MeV with relative energy spread smaller than 1% has been measured for the first time. Using higher laser energy PIC simulations predicted that 3 GeV electron beam with 0.9% should be produced in this scheme after 3.8 cm propagation length. In collaboration with J. Faure and C. Rechatin, Laboratoire d'Optique Appliqu'ee, 'Ecole Nationale Sup'erieure de Te...
... with their injection velocity parallel to the propagation axis (r(0) = r0 and dr/dt(0) = 0). ... more ... with their injection velocity parallel to the propagation axis (r(0) = r0 and dr/dt(0) = 0). An analytic solution to this differential equation exists and under the assumption √ 2γ0β0E0/Ez ≫ 1, the output angle θ ≈ vr/vz ≈ c−1 dr/dt simplifies to ... [22] Tsung FS, Ren C., Silva LO, Mori ...
ABSTRACT Gamma-ray beams with optimal and tuneable size, temperature, and dose are of great inter... more ABSTRACT Gamma-ray beams with optimal and tuneable size, temperature, and dose are of great interest for a large variety of applications. These photons can be produced by the conversion of energetic electrons through the bremsstrahlung process in a dense material. This work presents the experimental demonstration of 30 mu m resolution radiography of dense objects using an optimized gamma-ray source, produced with a high-quality electron beam delivered by a compact laser-plasma accelerator. (C) 2011 American Institute of Physics. [doi:10.1063/1.3604013]
Since its creation, LULI has given an important contribution to laser plasma physics and Inertial... more Since its creation, LULI has given an important contribution to laser plasma physics and Inertial Confinement Fusion studies. We will review some major results obtained these last two years with a 600 ps laser chain and with the recent 100-TW, 300fs ultra-intense laser chain. These result cover a wide spectrum of laser plasma physics research such as laser plasma interaction,
An experiment has been performed with the LULI Multi-TeraWatt Laser. The acceleration of electron... more An experiment has been performed with the LULI Multi-TeraWatt Laser. The acceleration of electrons injected in a plasma wave generated by the laser wakefield mechanism has been observed with a maximum energy gain of 1.5 MeV. It has been shown that the electrons deflected during the interaction, could scatter on the walls of the experimental chamber and fake a high
Nonlinear Thomson scattering radiation has been observed from relativistic laser plasma interacti... more Nonlinear Thomson scattering radiation has been observed from relativistic laser plasma interaction. We found that this radiative process is dominant for very high intensity at which point the relativistic scattering of the laser light originates from MeV energy electrons inside the plasma
We have produced polychromatic x-ray radiation by linear and non-linear Thomson scattering of an ... more We have produced polychromatic x-ray radiation by linear and non-linear Thomson scattering of an intense femtosecond laser on relativistic electrons accelerated in a helium plasma. The principle is the following. When relativistic electrons are submitted to a strong femtosecond laser pulse they experience strong accelerations and emit a femtosecond burst of nonlinear Thomson scattering radiation. This was demonstrated in the
An experimental study of shocks with astrophysical relevance is performed with the high energy de... more An experimental study of shocks with astrophysical relevance is performed with the high energy density laser of the LULI, at the Ecole Polytechnique. The peculiarity of these shocks is the strong coupling between radiation and hydrodynamics which leads to a structure governed by a radiative precursor. A new experiment has been performed this year where we have observed shocks identified
ABSTRACT An integral back-transform has been developed to retrieve the polar magnetic component i... more ABSTRACT An integral back-transform has been developed to retrieve the polar magnetic component in a cylindrically symmetric plasma from a single projection. The formula is derived from parallel forward Radon transform (Abel transform) of a source-free vector field. Two numerical schemes are proposed to solve the backward transform. These schemes have been tested successfully with predefined plasma parameters. The practical application to the analysis of experimental Faraday rotation measurements is also presented, leading to the reconstruction of the transverse profile of the magnetic field.
Experimental and theoretical results on the stimulated Raman backscattering (SRS) reflectivity of... more Experimental and theoretical results on the stimulated Raman backscattering (SRS) reflectivity of a short laser pulse (120 fs) interaction with an optically ionized helium gas are presented. The reflectivity is measured as a function of the gas pressure from 1 to 100 Torr. A monodimensional (1-D) theoretical model, including the refraction induced during the ionization process, describes the dependence of
The all optical external injection scheme that we will use with two colliding laser pulses allows... more The all optical external injection scheme that we will use with two colliding laser pulses allows a way to stabilize the injection of electrons into the plasma wave, and to easily tune the energy of the output beam by changing the longitudinal position of the injection. The charge and relative energy spread are also controllable by tuning parameters such as the injection intensity and its polarization. We report here on the control of the e-beam parameters, on the e-beam parameters that will be used for the conception and design of the emittance meter and on the experimental arrangement on which emittance measurement experiments will be achieved.
ABSTRACT We demonstrate the generation of high quality electron beams resulting from the interact... more ABSTRACT We demonstrate the generation of high quality electron beams resulting from the interaction of ultrashort and ultraintense laser pulses with underdense plasmas. The electron energy distribution is quasi-monoenergetic and peaks at 170 MeV
Laser Acceleration of Electrons, Protons, and Ions II; and Medical Applications of Laser-Generated Beams of Particles II; and Harnessing Relativistic Plasma Waves III, 2013
ABSTRACT We report on an experimental demonstration of laser wake field electron acceleration usi... more ABSTRACT We report on an experimental demonstration of laser wake field electron acceleration using few-milijoule laser pulses tightly focused on a 100 μm scale gas target. Using a comparatively low energy pulse has the benefit of a more compact system with a high repetition rate (typically kHz), which can prove useful for both practical applications and better statistical studies of laser plasma interactions. A proof-of-principle experiment was conducted to demonstrate the applicability of such electron sources from laser plasma wake field accelerator for ultrafast electron diffraction.
... Focusing a laser pulse with a spherical or an axial lens onto the edge of the gas ... The bac... more ... Focusing a laser pulse with a spherical or an axial lens onto the edge of the gas ... The backing pressure is also limited, as the installation of an additional pump complicates the ... The resultingjet should be stable and quasistationary to simplify the synchronization of the valve and ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2011
... Permissions & Reprints. Optimization of gamma-ray beams produced by a laser-plasma accele... more ... Permissions & Reprints. Optimization of gamma-ray beams produced by a laser-plasma accelerator. A. Ben-Ismaïl a , b , Corresponding Author Contact Information , E-mail The Corresponding Author , J. Faure a and V. Malka a. ...
It is known that relativistic laser plasma interactions can already today induce accelerating fie... more It is known that relativistic laser plasma interactions can already today induce accelerating fields beyond some TV/m, which are indeed capable to efficiently accelerate plasma background electrons as well as protons. An introduction to the current state of the art will be given and possible applications of these optically induced charged particle sources will be discussed.
Stable and high quality electron beams are produced when two laser pulses collide in underdense p... more Stable and high quality electron beams are produced when two laser pulses collide in underdense plasmas. In addition to the improvement of the stability of the electron beam, the use of a second laser pulse allows the control of the electron beam parameters (energy, relative energy spread, and charge). The experimental features are well explained by the use of PIC simulations which underline physics processes which were not predicted by fluid model. This control is obtained by changing laser pulse energy, laser pulses polarization or electron density. With a total of 1 J laser energy, a 10 pC electron beam at 200 MeV with relative energy spread smaller than 1% has been measured for the first time. Using higher laser energy PIC simulations predicted that 3 GeV electron beam with 0.9% should be produced in this scheme after 3.8 cm propagation length. In collaboration with J. Faure and C. Rechatin, Laboratoire d'Optique Appliqu'ee, 'Ecole Nationale Sup'erieure de Te...
... with their injection velocity parallel to the propagation axis (r(0) = r0 and dr/dt(0) = 0). ... more ... with their injection velocity parallel to the propagation axis (r(0) = r0 and dr/dt(0) = 0). An analytic solution to this differential equation exists and under the assumption √ 2γ0β0E0/Ez ≫ 1, the output angle θ ≈ vr/vz ≈ c−1 dr/dt simplifies to ... [22] Tsung FS, Ren C., Silva LO, Mori ...
ABSTRACT Gamma-ray beams with optimal and tuneable size, temperature, and dose are of great inter... more ABSTRACT Gamma-ray beams with optimal and tuneable size, temperature, and dose are of great interest for a large variety of applications. These photons can be produced by the conversion of energetic electrons through the bremsstrahlung process in a dense material. This work presents the experimental demonstration of 30 mu m resolution radiography of dense objects using an optimized gamma-ray source, produced with a high-quality electron beam delivered by a compact laser-plasma accelerator. (C) 2011 American Institute of Physics. [doi:10.1063/1.3604013]
Since its creation, LULI has given an important contribution to laser plasma physics and Inertial... more Since its creation, LULI has given an important contribution to laser plasma physics and Inertial Confinement Fusion studies. We will review some major results obtained these last two years with a 600 ps laser chain and with the recent 100-TW, 300fs ultra-intense laser chain. These result cover a wide spectrum of laser plasma physics research such as laser plasma interaction,
An experiment has been performed with the LULI Multi-TeraWatt Laser. The acceleration of electron... more An experiment has been performed with the LULI Multi-TeraWatt Laser. The acceleration of electrons injected in a plasma wave generated by the laser wakefield mechanism has been observed with a maximum energy gain of 1.5 MeV. It has been shown that the electrons deflected during the interaction, could scatter on the walls of the experimental chamber and fake a high
Nonlinear Thomson scattering radiation has been observed from relativistic laser plasma interacti... more Nonlinear Thomson scattering radiation has been observed from relativistic laser plasma interaction. We found that this radiative process is dominant for very high intensity at which point the relativistic scattering of the laser light originates from MeV energy electrons inside the plasma
We have produced polychromatic x-ray radiation by linear and non-linear Thomson scattering of an ... more We have produced polychromatic x-ray radiation by linear and non-linear Thomson scattering of an intense femtosecond laser on relativistic electrons accelerated in a helium plasma. The principle is the following. When relativistic electrons are submitted to a strong femtosecond laser pulse they experience strong accelerations and emit a femtosecond burst of nonlinear Thomson scattering radiation. This was demonstrated in the
An experimental study of shocks with astrophysical relevance is performed with the high energy de... more An experimental study of shocks with astrophysical relevance is performed with the high energy density laser of the LULI, at the Ecole Polytechnique. The peculiarity of these shocks is the strong coupling between radiation and hydrodynamics which leads to a structure governed by a radiative precursor. A new experiment has been performed this year where we have observed shocks identified
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