Luca Fedeli

Atomic Energy and Alternative Energies Commission | CEA · Institut rayonnement matière de Saclay (IRAMIS)

We propose a scheme to explore regimes of strong-field quantum electrodynamics (SF QED) otherwise unattainable with the currently available laser technology. The scheme relies on relativistic plasma mirrors curved by radiation pressure to boost the intensity of petawatt-class laser pulses by Doppler effect and focus them to extreme field intensitie...

Physical scenarios where the electromagnetic fields are so strong that Quantum ElectroDynamics (QED) plays a substantial role are one of the frontiers of contemporary plasma physics research. Investigating those scenarios requires state-of-the-art Particle-In-Cell (PIC) codes able to run on top high-performance computing machines and, at the same t...

Near-critical plasmas irradiated at ultra-high laser intensities (I > 1018W/cm2) allow to improve the performances of laser-driven particle and radiation sources and to explore scenarios of great astrophysical interest. Near-critical plasmas with controlled properties can be obtained with nanostructured low-density materials. By means of 3D Particl...

Ion beam analysis techniques are among the most powerful tools for advanced material characterization. Despite their growing relevance in a widening number of fields, most ion beam analysis facilities still rely on the oldest accelerator technologies, with severe limitations in terms of portability and flexibility. In this work we thoroughly addres...

The generation of energetic electron bunches by the interaction of a short, ultra-intense ($I>10^{19} \textrm{W/cm}^2$) laser pulse with "grating" targets has been investigated in a regime of ultra-high pulse-to-prepulse contrast ($10^{12}$). For incidence angles close to the resonant condition for Surface Plasmon (SP) excitation, a strong electron...

Developing complex, reliable advanced accelerators requires a coordinated, extensible, and comprehensive approach in modeling, from source to the end of beam lifetime. We present highlights in Exascale Computing to scale accelerator modeling software to the requirements set for contemporary science drivers. In particular, we present the first laser...

The advent of Petawatt-class laser systems allows generating electro-magnetic fields of unprecedented strength in a controlled environment, driving in-creasingly more efforts to probe yet unobserved processes through their interaction with the quantum vacuum. Still, the lowest intensity scale governing these effects lies orders of magnitude beyond...

Electromagnetic particle-in-cell (PIC) codes are widely used to perform computer simulations of a variety of physical systems, including fusion plasmas, astrophysical plasmas, plasma wakefield particle accelerators, and secondary photon sources driven by ultra-intense lasers. In a PIC code, Maxwell's equations are solved on a grid with a numerical...

The advent of Petawatt-class laser systems allows generating electro-magnetic fields of unprecedented strength in a controlled environment, driving increasingly more efforts to probe yet unobserved processes through their interaction with the quantum vacuum. Still, the lowest intensity scale governing these effects lies orders of magnitude beyond f...

Physical scenarios where the electromagnetic fields are so strong that Quantum ElectroDynamics (QED) plays a substantial role are one of the frontiers of contemporary plasma physics research. Investigating those scenarios requires state-of-the-art Particle-In-Cell (PIC) codes able to run on top high-performance computing machines and, at the same t...

The interaction between intense 30 fs laser pulses and foam-coated 1.5 μm-thick Al foils in the relativistic regime (up to 5 × 1020 W cm-2) is studied to optimize the laser energy conversion into laser-accelerated protons. A significant enhancement is observed for foam targets in terms of proton cut-off energy (18.5 MeV) and number of protons above...

WarpX is a general purpose electromagnetic particle-in-cell code that was originally designed to run on many-core CPU architectures. We describe the strategy, based on the AMReX library, followed to allow WarpX to use the GPU-accelerated nodes on OLCF’s Summit supercomputer, a strategy we believe will extend to the upcoming machines Frontier and Au...

Electromagnetic particle-in-cell (PIC) codes are widely used to perform computer simulations of a variety of physical systems, including fusion plasmas, astrophysical plasmas, plasma wakefield particle accelerators, and secondary photon sources driven by ultra-intense lasers. In a PIC code, Maxwell's equations are solved on a grid with a numerical...

The fully electromagnetic particle-in-cell code WarpX is being developed by a team of the U.S. DOE Exascale Computing Project (with additional non-U.S. collaborators on part of the code) to enable the modeling of chains of tens to hundreds of plasma accelerator stages on exascale supercomputers, for future collider designs. The code is combining th...

WarpX is a general purpose electromagnetic particle-in-cell code that was originally designed to run on many-core CPU architectures. We describe the strategy followed to allow WarpX to use the GPU-accelerated nodes on OLCF's Summit supercomputer, a strategy we believe will extend to the upcoming machines Frontier and Aurora. We summarize the challe...

We propose a scheme to explore regimes of strong-field Quantum Electrodynamics (SF-QED) otherwise unattainable with the currently available laser technology. The scheme relies on relativistic plasma mirrors curved by radiation pressure to boost the intensity of PetaWatt-class laser pulses by Doppler effect and focus them to extreme field intensitie...

Laser-driven ion sources are interesting for many potential applications, from nuclear medicine to material science. A promising strategy to enhance both ion energy and number is given by Double-Layer Targets (DLTs), i.e. micrometric foils coated by a near-critical density layer. Optimization of DLT parameters for a given laser setup requires a dee...

Laser-driven ion sources are approaching the requirements for several applications in materials and nuclear science. Relying on compact, table-top, femtosecond laser systems is pivotal to enable most of these applications. However, the moderate intensity of these systems (I ≥10^19 W/cm^2 ) could lead to insufficient energy and total charge of the a...

The investigation of superintense laser-driven ion sources and their potential applications offers unique opportunities for multidisciplinary research. Plasma physics can be combined with materials and nuclear science, radiation detection and advanced laser technology, leading to novel research challenges of great fundamental and applicative intere...

Ion beam analysis techniques are among the most powerful tools for advanced materials characterization. Despite their growing relevance in a widening number of fields, most ion beam analysis facilities still rely on the oldest accelerator technologies, with severe limitations in terms of portability and flexibility. In this work we thoroughly addre...

Experiments on the excitation of propagating surface plasmons (SPs) by an ultrashort, high intensity laser interaction with grating targets are reviewed. At intensities exceeding 10¹⁹ W cm⁻² on target, i.e., in the strongly relativistic regime of electron dynamics, multi-megaelectronvolt electrons are accelerated by the SP field as dense bunches co...

Experiments on the excitation of propagating surface plasmons (SPs) by ultrashort, high intensity laser interaction with "grating" targets are reviewed. At intensities exceeding $10^{19}~\mbox{W cm}^{-2}$ on target, i.e. in the strongly relativistic regime of electron dynamics, multi-MeV electrons are accelerated by the SP field as dense bunches co...

The emission of high-order harmonics in the extreme ultraviolet range from the interaction of a short, intense laser pulse with a grating target is investigated experimentally. When resonantly exciting a surface plasmon, both the intensity and the highest order observed for the harmonic emission along the grating surface increase with respect to a...

The excitation of surface plasmons with ultra-intense ($I\sim 5\times 10^{19}$ W/cm$^2$), high contrast ($\sim 10^{12}$) laser pulses on periodically-modulated solid targets has been recently demonstrated to produce collimated bunches of energetic electrons along the target surface [Fedeli et al., Phys. Rev. Lett. 116, 5001 (2016)]. Here we report...

A concept for the efficient generation of surface plasmon polaritons (SPPs) with a duration of very few cycles is presented. The scheme is based on grating coupling and laser pulses with wavefront rotation (WFR), so that the resonance condition for SPP excitation is satisfied only for a time window shorter than the driving pulse. The feasibility an...

Structured targets offer great control over ultra-intense laser-plasma interaction, allowing the optimization of laser-target coupling for specific applications. By means of particle-in-cell simulations we investigated three applications in particular: high-order harmonic generation (HHG) with grating targets, enhanced target coupling with multilay...

In this manuscript the role of plasmonic effects in several scenarios involving ultra-high intensity laser-matter interaction was investigated.

As in many research fields, numerical simulations play an important role in plasma physics. Indeed, plasmas are complex physical systems and in several scenarios analytical theories are of limited applicability. Numerical simulations are often required to clarify the physical processes at play in certain conditions or to prepare experimental activi...

In this chapter several physical scenarios involving High Field Plasmonics effects are discussed.

The main result described in this chapter is the first observation of electron acceleration by relativistic surface plasmons excited with ultra-high intensity laser pulses (\( I > 10^{18}\, \text {W/cm}^2\)) interacting with grating targets. The experimental data are supported by three-dimensional numerical simulations and a theoretical model, whic...

This dissertation deals manly with the attempt to extend the study of plasmonic effects in the ultra-high intensity (beyond \(10^{18}\,\text {W/cm}^2\)) laser-matter interaction. Plasmonics, which is the study of surface plasmons, is a mature research field. However, surface plasmons are generally excited with low-intensity laser pulses. The study...

The object of the present chapter is the study (both experimental and numerical) of ion acceleration schemes with multi-layer foam attached targets.

Ultra-short laser-matter interaction at extreme intensities is a broad research field with several potential applications, including electron acceleration, ion acceleration, ultra-intense x-ray and \(\gamma \) sources, pulsed neutron sources and laboratory astrophysics (see Chap. 2). Laser-driven sources of charged particles or photons are characte...

Laser interaction with uniform and nanostructured near-critical plasmas has been investigated by means of 2D particle-in-cell simulations. The effect of a nanostructure (modeled as a collection of solid-density nanospheres) on energy absorption and radiative losses has been assessed in a wide range of laser intensities (normalized amplitude a0 = 1...

This thesis describes pioneering research on the extension of plasmonics schemes to the regime of high-intensity lasers. By presenting a rich and balanced mix of experimentation, theory and simulation, it provides a comprehensive overview of the emerging field of high field plasmonics, including open issues and perspectives for future research. Com...

Thanks to its high melting point and thermal conductivity, tungsten (W) is among the most promising candidates as plasma facing material (PFM) in fusion reactors (e.g. ITER, DEMO), where the resistance to extreme thermal loads during steady and transient operating conditions is a key requirement. Because of their peculiar properties, which can sign...

The role of relativistic surface plasmons (SPs) in high order harmonic emission from laser-irradiated grating targets has been investigated by means of particle-in-cell simulations. SP excitation drives a strong enhancement of the intensity of harmonics, particularly in the direction close to the surface tangent. The SP-driven enhancement overlaps...

In this work we investigate electron heating induced by intense laser interaction with micrometric flat solid foils in the context of laser-driven ion acceleration. We propose a simple law to predict the electron temperature in a wider range of laser parameters with respect to commonly used existing models. An extensive two-dimensional (2D) and 3D...

The development of novel target concepts is crucial to make laser-driven acceleration of ion beams suitable for applications. We tested double-layer targets formed of an ultralow density nanostructured carbon layer (∼7 mg/cm3, 8–12 μm–thick) deposited on a μm–thick solid Al foil. A systematic increase in the total number of the accelerated ions (pr...

We report on the development of foam-based double-layer targets (DLTs) for laser-driven ion acceleration. Foam layers with a density of a few mg cm−3 and controlled thickness in the 8–36 μm range were grown on μm-thick Al foils by pulsed laser deposition (PLD). The DLTs were experimentally investigated by varying the pulse intensity, laser polarisa...

The interaction of low intensity laser pulses with metal nano-structures is at the basis of plasmonics and the excitation of surface plasmon polaritons (SP) is one of its building blocks. Some of the configurations adopted in classical plasmonics can be explored considering high intensity lasers interacting with properly structured targets. SP exci...

We present a Vlasov, i.e. a kinetic Eulerian simulation study of nonlinear collisionless ion-acoustic shocks and solitons excited by an intense laser interacting with an overdense plasma. The use of the Vlasov code avoids problems with low particle statistics and allows a validation of particle-in-cell results. A simple original correction to the s...

In an experiment at the laser facility ECLIPSE of the CELIA laboratory, University of Bordeaux, we measure the reflectivity of spherically bent crystals that are commonly used to investigate the propagation of fast electrons through the Kα radiation they generate in matter. The experimental reflectivity compares well with predictions from a ray-tra...

The generation of energetic electrons by the interaction of a short laser pulse with solid "grating" targets, having a periodic groove on the irradiated surface, has been investigated in a regime of ultrahigh contrast (10(12)) and relativistically strong intensity (> 10(19)W/cm(2)). A strong enhancement of both the energy and number of electrons em...

We discuss a detailed strong and weak scaling analysis of PICCANTE, an open source, massively parallel, fully-relativistic Particle-In-Cell (PIC) code. PIC codes are widely used in plasma physics and astrophysics to study the cases where kinetic effects are relevant. PICCANTE is primarily developed to study laser-plasma interaction. Within a PRACE...

The evolution of the filamentation instability produced by two counter-streaming pair plasmas is studied with particle-in-cell (PIC) simulations in both one (1D) and two (2D) spatial dimensions. Radiation friction effects on particles are taken into account. After an exponential growth of both the magnetic field and the current density, a nonlinear...

The acceleration of dense targets driven by the radiation pressure of high-intensity lasers leads to a Rayleigh-Taylor instability (RTI) with rippling of the interaction surface. Using a simple model it is shown that the self-consistent modulation of the radiation pressure caused by a sinusoidal rippling affects substantially the wavevector spectru...

The evolution of the filamentation instability produced by two counter-streaming pair plasmas is studied with particle-in-cell (PIC) simulations in both one (1D) and two (2D) spatial dimensions. Radiation friction effects on particles are taken into account. During the nonlinear stage of the instability, a strong broadening of the particle energy s...

Articles you may be interested in Combined x-ray scattering, radiography, and velocity interferometry/streaked optical pyrometry measurements of warm dense carbon using a novel technique of shock-and-releasea) Phys. Plasmas 21, 056309 (2014); 10.1063/1.4876613 High-energy, high-resolution x-ray imaging on the Trident short-pulse laser facilitya) Re...

The relativistic Vlasov equation is integrated numerically in an Eulerian framework in order to investigate the phase space development of the wavebreak of a relativistic Langmuir wave in a thermal plasma. Relativistic kinematic and beam loading effects lead to a “differential retardation” in the time required by the electrons to evolve in phase sp...