arXiv subjects

Henri Vincenti

Publications and source records attributed to Henri Vincenti.

13 recordsLinked to original sources

arXiv2026

Generation and control of Doppler harmonics approaching $10^{22}\textrm{W/cm}^2$ on plasma mirrors

In this letter, we report Doppler harmonic generation with a relativistic plasma mirror at unprecedented intensities $>10^{21} ~\textrm{W/cm}^2$ using a PetaWatt-class laser. We show that beyond a few $10^{21} ~\textrm{W/cm}^2$ a precise control of the laser contrast at the sub-picosecond time scale becomes essential to drive the efficient generation of high-order harmonics. Such control is paramount for deploying plasma mirrors in high-field applications at PetaWatt-class laser facilities, including, for instance, their use as intensity boosters in the pursuit of the strong-field regime of quantum electrodynamics.

physics.plasm-ph↗

arXiv2023

Beam Delivery and Beamstrahlung Considerations for Ultra-High Energy Linear Colliders

As part of the Snowmass'21 community planning excercise, the Advanced Accelerator Concepts (AAC) community proposed future linear colliders with center-of-mass energies up to 15 TeV and luminosities up to 50$\times10^{34}$ cm$^{-2}$s$^{-1}$ in a compact footprint. In addition to being compact, these machines must also be energy efficient. We identify two challenges that must be addressed in the design of these machines. First, the Beam Delivery System (BDS) must not add significant length to the accelerator complex. Second, beam parameters must be chosen to mitigate beamstrahlung effects and maximize the luminosity-per-power of the machine. In this paper, we review advances in plasma lens technology that will help to reduce the length of the BDS system and we detail new Particle-in-Cell simulation studies that will provide insight into beamstrahlung mitigation techniques. We apply our analysis to both $e^+e^-$ and $γγ$ colliders.

physics.acc-ph↗

arXiv2023

Light-Matter Interaction Near the Schwinger Limit Using Tightly Focused Doppler-Boosted Lasers

The Schwinger limit could be approached by focusing to its diffraction limit the light reflected by a plasma mirror irradiated by a multi-petawatt laser. We explore numerically the interaction between such intense light and matter. We find that the interaction with a relativistic counterpropagative electron beam would enable the exploration of the fully nonperturbative regime of strong-field quantum electrodynamics (SF-QED), while the interaction with an initially solid target leads to a profusion of SF-QED effects that retroact on the laser-plasma interaction. We observe in both scenarios the formation of relativistic attosecond electron-positron jets with very high densities.

physics.plasm-ph↗

arXiv2023

From Compact Plasma Particle Sources to Advanced Accelerators with Modeling at Exascale

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-plasma modeling on an exaflop supercomputer using the US DOE Exascale Computing Project WarpX. Leveraging developments for Exascale, the new DOE SCIDAC-5 Consortium for Advanced Modeling of Particle Accelerators (CAMPA) will advance numerical algorithms and accelerate community modeling codes in a cohesive manner: from beam source, over energy boost, transport, injection, storage, to application or interaction. Such start-to-end modeling will enable the exploration of hybrid accelerators, with conventional and advanced elements, as the next step for advanced accelerator modeling. Following open community standards, we seed an open ecosystem of codes that can be readily combined with each other and machine learning frameworks. These will cover ultrafast to ultraprecise modeling for future hybrid accelerator design, even enabling virtual test stands and twins of accelerators that can be used in operations.

physics.acc-ph↗

arXiv2022

Quantum vacuum processes in the extremely intense light of relativistic plasma mirror sources

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 foreseen capabilities, so that such endeavor is expected to remain extremely challenging. In recent years, however, plasma mirrors have emerged as a promising bridge across this gap, by enabling the conversion of intense infrared laser pulses into coherently focused Doppler harmonic beams lying in the X-UV range. In this work, we present quantitative predictions on the quantum vacuum signatures produced when such beams are focused to intensities between $10^{24}$ and $10^{28}\ \mathrm{W.cm}^{-2}$ . These signatures, which notably include photon-photon scattering and electron-positron pair creation, are obtained using state-of-the-art massively parallel numerical tools. In view of identifying experimentally favorable configurations, we also consider the coupling of the focused harmonic beam with an auxiliary optical beam, and provide comparison with other established schemes. Our results show that a single coherently focused harmonic beam can produce as much scattered photons as two infrared pulses in head-on collision, and confirm that the coupling of the harmonic beam to an auxiliary beam gives rise to significant levels of inelastic scattering, and hence holds the potential to strongly improve the attainable signal to noise ratios in experiments.

physics.optics↗

arXiv2021

PICSAR-QED: a Monte Carlo module to simulate Strong-Field Quantum Electrodynamics in Particle-In-Cell codes for exascale architectures

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 time, able to simulate strong-field QED processes. This work presents the PICSAR-QED library, an open-source, portable implementation of a Monte Carlo module designed to provide modern PIC codes with the capability to simulate such processes, and optimized for high-performance computing. Detailed tests and benchmarks are carried out to validate the physical models in PICSAR-QED, to study how numerical parameters affect such models, and to demonstrate its capability to run on different architectures (CPUs and GPUs). Its integration with WarpX, a state-of-the-art PIC code designed to deliver scalable performance on upcoming exascale supercomputers, is also discussed and validated against results from the existing literature.

physics.plasm-ph↗

arXiv2021

A Hybrid Nodal-Staggered Pseudo-Spectral Electromagnetic Particle-In-Cell Method with Finite-Order Centering

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 method of choice. This article focuses on pseudo-spectral analytical time-domain (PSATD) algorithms and presents a novel hybrid PSATD PIC scheme that combines the respective advantages of standard nodal and staggered methods. The novelty of the hybrid scheme consists in using finite-order centering of grid quantities between nodal and staggered grids, in order to combine the solution of Maxwell's equations on a staggered grid with the deposition of charges and currents and the gathering of electromagnetic forces on a nodal grid. The correctness and performance of the novel hybrid scheme are assessed by means of numerical tests that employ different classes of PSATD equations in a variety of physical scenarios, ranging from the modeling of electron-positron pair creation in vacuum to the simulation of laser-driven and particle beam-driven plasma wakefield acceleration. It is shown that the novel hybrid scheme offers significant numerical and computational advantages, compared to purely nodal or staggered methods, for all the test cases presented.

physics.comp-ph↗

arXiv2020

Probing strong-field QED with Doppler-boosted PetaWatt-class lasers

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 intensities. We show that very clear SF-QED signatures could be observed by placing a secondary target where the boosted beam is focused.

physics.plasm-ph↗

arXiv2018

A generalized massively parallel ultra-high order FFT-based Maxwell solver

Dispersion-free ultra-high order FFT-based Maxwell solvers have recently proven to be paramount to a large range of applications, including the high-fidelity modeling of high-intensity laser-matter interactions with Particle-In-Cell (PIC) codes. To enable a massively parallel scaling of these solvers, a novel parallelization technique was recently proposed, which consists in splitting the simulation domain into several processor sub-domains, with guard regions appended at each sub-domain boundaries. Maxwell's equations are advanced independently on each sub-domain using local shared-memory FFTs (instead of a single distributed global FFT). This implies small truncation errors at sub-domain boundaries, the amplitude of which depends on guard regions sizes and order of the Maxwell solver. For a moderate number of guard cells (<10) , this 'local' technique proved to be highly scalable on up to a million cores. Yet, depending on the targeted applications, the number of guard cells required to mitigate truncations errors might be very large, which would severely limit the parallel efficiency of this technique due to the large volume of guard cells to be exchanged between sub-domains. In this context, we propose a novel 'hybrid' parallelization technique that ensures very good scaling of FFT-based solvers with an arbitrarily high number of guard cells. It consists in performing distributed FFTs on local groups of processors with guard regions now appended to boundaries of each group of processors. A dual domain decomposition method is used for the Maxwell solver and other parts of the PIC cycle to keep the simulation load-balanced. This 'hybrid' technique was implemented in the open source exascale library PICSAR. Benchmarks show that for a large number of guard cells ($>16$), the 'hybrid' technique offers a $\times 3$ speed-up and $\times 8$ memory savings compared to the 'local' one.

physics.comp-ph↗

arXiv2018

Achieving extreme light intensities using relativistic plasma mirrors

In this letter, cutting-edge 3D Particle-In-Cell simulations are used to demonstrate that so-called relativistic plasma mirrors irradiated by PetaWatt (PW) lasers and naturally curved by laser radiation pressure can be used to tightly focus Doppler-generated harmonics to extreme intensities between $10^{25}-10^{26}W.cm^{-2}$. Those simulations are then employed to develop and validate a general 3D model of harmonic focusing by a curved relativistic plasma mirror. Finally, the insight gained from this model is used to propose novel all-optical techniques that would further increase the plasma mirror curvature with the ultimate goal of approaching the Schwinger limit.

physics.plasm-ph↗

arXiv2018

On the physics of electron ejection from laser-irradiated overdense plasmas

Using 1D and 2D PIC simulations, we describe and model the backward ejection of electron bunches when a laser pulse reflects off an overdense plasma with a sharp density gradient on its front side. The dependence on the laser intensity and gradient scale length is studied. It is found that during each laser period the incident laser pulse generates a large charge-separation field, or plasma capacitor, which accelerates an attosecond bunch of electrons towards vacuum. This process is maximized for short gradient scale lengths and collapses when the gradient scale length is comparable to the laser wavelength. We develop a model that reproduces the electron dynamics and the dependence on laser intensity and gradient scale length. This process is shown to be strongly linked with high-harmonics generation via the Relativistic Oscillating Mirror mechanism.

physics.plasm-ph↗

arXiv2017

Ultrahigh-order Maxwell solver with extreme scalability for electromagnetic PIC simulations of plasmas

The advent of massively parallel supercomputers, with their distributed-memory technology using many processing units, has favored the development of highly-scalable local low-order solvers at the expense of harder-to-scale global very high-order spectral methods. Indeed, FFT-based methods, which were very popular on shared memory computers, have been largely replaced by finite-difference (FD) methods for the solution of many problems, including plasmas simulations with electromagnetic Particle-In-Cell methods. For some problems, such as the modeling of so-called "plasma mirrors" for the generation of high-energy particles and ultra-short radiations, we have shown that the inaccuracies of standard FD-based PIC methods prevent the modeling on present supercomputers at sufficient accuracy. We demonstrate here that a new method, based on the use of local FFTs, enables ultrahigh-order accuracy with unprecedented scalability, and thus for the first time the accurate modeling of plasma mirrors in 3D.

physics.comp-ph↗

arXiv2017

Accurate modeling of plasma acceleration with arbitrary order pseudo-spectral particle-in-cell methods

Particle in Cell (PIC) simulations are a widely used tool for the investigation of both laser- and beam-driven plasma acceleration. It is a known issue that the beam quality can be artificially degraded by numerical Cherenkov radiation (NCR) resulting primarily from an incorrectly modeled dispersion relation. Pseudo-spectral solvers featuring infinite order stencils can strongly reduce NCR, or even suppress it, and are therefore well suited to correctly model the beam properties. For efficient parallelization of the PIC algorithm, however, localized solvers are inevitable. Arbitrary order pseudo-spectral methods provide this needed locality. Yet, these methods can again be prone to NCR. Here, we show that acceptably low solver orders are sufficient to correctly model the physics of interest, while allowing for parallel computation by domain decomposition.

physics.acc-ph↗