Probing strong-field Quantum Electrodynamics with Doppler-boosted laser beams

National audiencePhysical scenarios characterized by electromagnetic fields so strong that quantum electro-dynamics (SF-QED) plays a substantial role are one of the frontiers of contemporary plasma physics research. At LIDYL we study strategies to use optical devices called "plasma mirrors" curved by radiation pressure to boost the intensities of existing ultra-intense lasers by the Doppler effect and focus them to extreme field intensities, high-enough to use them to study SF-QED. In this contribution we present such strategies as well as the numerical tools required to model these physical scenarios. In particular, we will present WarpX, a state-of-the-art, open- source Particle-In-Cell code conceived to address the challenges of computing at the exascale, as well as PICSAR-QED, a portable Monte Carlo module providing WarpX with the capability of simulating the SF-QED phenomena that are usually the mostrelevan

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

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.Comment: 21 pages, 5 figure

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

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

International audienceThe 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

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

International audiencePlasma mirrors can boost the intensity of high-power lasers by several orders of magnitude [1]. This intensity gain comes from the relativistic oscillation of the plasma surface, whichperiodically compresses the incident laser energy in a small volume by the relativistic Dopplereffect. With this method, the simple reflection of a PW-class laser on a solid target can lead tolight with a peak intensity in the 1025-1026 W/cm2range. We have previously shown that theseintensities could enhance the signatures of Strong-Field QED (SF-QED) processes [2], such asthe creation of electron-positron pairs by the Breit-Wheeler mechanism, in coming experiments.Yet, one of the most attractive aspects of this technique is that enormous intensities, in the1027-1029 W/cm2range, can in principle be reached with already achievable laser powers (1-10 PW) if the Doppler-boosted lasers are focused close to their diffraction limit [3, 4]. In thiscontribution, we will present results from 2D QED-PIC [5] simulations of light-matter interactions at these unexplored intensities, that approach the Schwinger limit (IS = 4.7 × 1029 W/cm2).We show that novel SF-QED dominated interaction regimes are attained.For instance, the interaction of a tightly focused Doppler boosted laser with a solid targetleads to an abundance of SF-QED events, with up to 70% of the laser energy eventually converted to high-energy γ photons, while the interaction with a counterpropagative relativisticelectron beam provides access to the fully nonperturbative regime of SF-QED [6]. Furthermore, a bunching of the generated particles by the laser is observed and leads to relativisticelectron-positron jets with extremely high density (up to 1034 m−3).References[1] Vincenti, H. Physical Review Letters, 123(10), 105001 (2019).[2] Fedeli, L., et al. Physical Review Letters, 127(11), 114801 (2021).[3] Gordienko, et al. Physical Review Letters, 94(10), 103903 (2005).[4] Quéré, F., and Vincenti, H. High Power Laser Science and Engineering, 9, e6 (2021).[5] Gonoskov, A., et al. Physical Review E, 92(2), 023305 (2015).[6] Fedotov, A. Journal of Physics: Conference Series (Vol. 826, No. 1, p. 012027) (2017)

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 (HPC) 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 HPC. 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

The WarpX code: Particle-In-Cell simulations at the exascale

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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 (HPC) 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 HPC. 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

PICSAR-QED: a Monte Carlo module to simulate strong-field quantum electrodynamics in particle-in-cell codes for exascale architectures

International audienceAbstract 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 (HPC) 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 HPC. 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