arXiv subjects

S. V. Bulanov

Publications and source records attributed to S. V. Bulanov.

At least 37 records · Page 2Linked to original sources

arXiv2023

Strong-field vacuum polarisation with high energy lasers

When photons propagate in vacuum they may fluctuate into matter pairs thus allowing the vacuum to be polarised. This linear effect leads to charge screening and renormalisation. When exposed to an intense background field a nonlinear effect can arise when the vacuum is polarised by higher powers of the background. This nonlinearity breaks the superposition principle of classical electrodynamics, allowing for light-by-light scattering of probe and background photons mediated through virtual pairs dressed by the background. Vacuum polarisation is a strong-field effect when all orders of interaction between the virtual pair and the background must be taken into account. In this investigation we show that multiple scattering processes of this type may be observed by utilising high-energy laser pulses with long pulse duration, such as are available at facilities like ELI Beamlines. In combination with appropriate sources of high-energy probe photons, multiple probe-background light-by-light scattering allows for testing the genuine nonlinear regime of strong-field QED. This provides access to the uncharted nonperturbative regime beyond the weak-field limit.

hep-ph↗

arXiv2023

Gamma-Flash Generation in Multi-Petawatt Laser-Matter Interactions

The progressive development of high power lasers over the last several decades, enables the study of $γ$-photon generation when an intense laser beam interacts with matter, mainly via inverse Compton scattering at the high intensity limit. $γ$-ray flashes are a phenomenon of broad interest, drawing attention of researchers working in topics ranging from cosmological scales to elementary particle scales. Over the last few years, a plethora of studies predict extremely high laser energy to $γ$-photon energy conversion using various target and/or laser field configurations. The aim of the present manuscript is to discuss several recently proposed $γ$-ray flash generation schemes, as a guide for upcoming $γ$-photon related experiments and for further evolution of the presently available theoretical schemes.

physics.plasm-ph↗

arXiv2023

On the capillary discharge in the high repetition rate regime

We investigate the main physical processes that limit the repetition rate of capillary discharges used in laser accelerators of electrons theoretically and with computer simulations. We consider processes in the capillary. We assume that a cooling system independently maintains temperature balance of the capillary, as well as a gas supply system and a vacuum system maintain conditions outside the capillary. The most important factor, determining the highest repetition rates in this case, is the capillary length, which governs a refilling time of the capillary by the gas. For a short capillary, used for acceleration of sub-GeV electron beams, the repetition rate approximately equal to 10 kHz, which is inversely proportional to the square of the capillary length. The effects of the capillary diameter, gas type and the gas density are weaker.

physics.plasm-ph↗

arXiv2023

Radiation from polarized vacuum in a laser-particle collision

The probability of photon emission of a charged particle traversing a strong field becomes modified if vacuum polarization is considered. This feature is important for fundamental quantum electrodynamics processes present in extreme astrophysical environments and can be studied in a collision of a charged particle with a strong laser field. We show that for today's available 700 GeV (6.5 TeV) protons and the field provided by the next generation of lasers, the emission spectra peak is enhanced due to vacuum polarization effect by 30% (suppressed by 65%) in comparison to the traditionally considered Compton process. This striking phenomenon offers a novel path to the laboratory-based manifestation of vacuum polarization.

hep-ph↗

arXiv2022

Design of plasma shutters for improved heavy ion acceleration by ultra-intense laser pulses

In this work, we investigate the application of the plasma shutters for heavy ion acceleration driven by a high-intensity laser pulse. We use particle-in-cell (PIC) and hydrodynamic simulations. The laser pulse, transmitted through the opaque shutter, gains a steep-rising front and its peak intensity is locally increased at the cost of losing part of its energy. These effects have a direct influence on subsequent ion acceleration from the ultrathin target behind the shutter. In our 3D simulations of silicon nitride plasma shutter and a silver target, the maximal energy of high-Z ions increases significantly when the shutter is included for both linearly and circularly polarized laser pulses. Moreover, application of the plasma shutter for linearly polarized pulse results in focusing of ions towards the laser axis in the plane perpendicular to the laser polarization. The generated high energy ion beam has significantly lower divergence compared to the broad ion cloud, generated without the shutter. The effects of prepulses are also investigated assuming a double plasma shutter. The first shutter can withstand the assumed sub-ns prepulse (treatment of ns and ps prepulses by other techniques is assumed) and the pulse shaping occursvia interaction with the second shutter. On the basis of our theoretical findings, we formulated an approach towards designing a double plasma shutter for high-intensity and high-power laser pulses and built a prototype.

physics.plasm-ph↗

arXiv2022

Development of LPA based hard X-ray sources at ELI Beamlines

We report the laser-plasma accelerator-based X-ray sources development at ELI beamlines. One of the main objectives of ELI Beamlines is to provide beams of ultrashort particle and complex X-ray sources to users from various research fields. Two hard X-ray betatron sources with high photon flux based on laser-plasma acceleration (LPA) are being commissioned. The first source is the Gammatron beamline located in Experimental Hall E2. It provides X-ray pulses of energies from 1-100 keV in betatron and up to a MeV in Compton scheme. A novel X-ray optics has been designed as a focusing optics of these hard X-ray sources for the user application. The second hard X-ray source based on LPA is being developed in the ELI plasma physics platform (P3) that will serve as an active diagnostics HED and Laboratory astrophysics, multi-beam experiments, and fundamental research. This source is now being commissioned, we will present the first experimental results. Besides, we have proposed a novel scheme for enhancing the X-ray flux based on betatron oscillations enhanced from nonlinear resonances due to interaction with a two-color laser field. In addition, we will introduce a novel optical probing technique with high sensitivity to characterize a low-density gas target for a laser-plasma accelerator. It has been achieved by employing multiple passes of the probe beam through the object and relay-imaging of the object between the individual passes.

physics.acc-ph↗

arXiv2022

On the new and old physics in the interaction of a radiating electron with the extreme electromagnetic field

We show that an all-optical configuration of the laser-electron collision in the $λ^{3}$ configuration based on 10 PW-class lasers presents a viable platform for reaching the range of parameters where a perturbative QED in strong external electromagnetic field breaks. This case is contingently referred to as a case of the nonperturbative QED; and this range of parameters is the intriguing goal from an experimental point of view because of a possible manifestation of a new physics of the interaction of a highly radiating particle with a strong electromagnetic field. We show that the strong field region can be reached by the electrons having the initial energy higher than 50 GeV. Our theoretical considerations are in agreement with three-dimensional particle-in-cell simulations. While increasing of the electron energy raises the number of electrons experiencing the strong field region, the observable signature of photon emission radiative correction in the strong field is expected to fade out when the electron energy surpasses the optimal value. This threshold of electron energy is identified and the parameters for achieving the nonperturbative limit of QED are provided.

hep-ph↗

arXiv2022

Highly Radiating Charged Particles in a Strong Electromagnetic Field

We consider highly radiating ultra-relativistic electrons in a strong external electromagnetic field. High intensity radiative losses and consequent $e^+e^-$-pair production, appearing in the frame of quantum electrodynamics, determine indirectly mass operator of electrons in the strong field. We calculate a leading term of the mass operator at asymptotically high energies of electrons in a strong constant field. We do not use any perturbation theory based on a low ratio of this mass operator to the electron mass $m_e$, but only the original small parameter of quantum electrodynamics, the fine structure constant, $α$. The analogous %but less nontrivial result is obtained for the polarization operator for photon propagator. These results resolve at least partially a very long-lasted controversy originating from traditional and straightforward application of perturbative approaches for description of highly radiating ultra-relativistic charged particles in a very strong electromagnetic fields.

hep-ph↗

arXiv2022

Ultrafast hard X-ray sources based on Relativistic Electrons at ELI Beamlines

We report the LWFA driven X-ray sources development at ELI beamlines. ELI Gammatron beamline provides X-ray pulses of energies from 1-100 keV in betatron scheme, and up to a MeV in Compton scheme. A state-of-the-art Ti:Sa diode-pumped HAPLS laser (10-30 J, 30 fs @10 Hz) is used as a driving laser for these X-ray sources. These sources are characterized with a low divergence (< 10 mrad), small source size (few μm), short pulse duration (a few fs) and photon flux up to1010 photons per pulse. In addition, a separate Betatron X-ray source is being developed in the ELI Plasma Physics Platform (P3)that will serve as an active diagnostics of various plasma physics experiments. P3 is dedicated to laboratory astrophysics, HED physics, multi-beam experiments, warm dense matter and fundamental research. Besides the presentation of the two X-ray sources, we will also introduce a novel optical probing method with increased interferometric sensitivity for characterization of low-density gas jets. The sensitivity is achieved together with using a novel optical configuration employing multiple passes of the probe beam through the object and relay-imaging of the object between the individual passes, and a short probing beam (405 nm).

physics.plasm-ph↗

arXiv2022

Laser ion acceleration from tailored solid targets with micron-scale channels

Laser ion acceleration is a promising concept for generation of fast ions using a compact laser-solid interaction setup. In this study, we theoretically investigate the feasibility of ion acceleration from the interaction of petawatt-scale laser pulses with a structured target that embodies a micron-scale channel filled with relativistically transparent plasma. Using 2D and 3D Particle-In-Cell (PIC) simulations and theoretical estimates, we show that it is possible to generate GeV protons with high volumetric charge and quasi-monoenergetic feature in the energy spectrum. We interpret the acceleration mechanism as a combination of Target Normal Sheath Acceleration and Radiation Pressure Acceleration. Optimal parameters of the target are formulated theoretically and verified using 2D PIC simulations. 3D PIC simulations and realistic preplasma profile runs with 2D PIC show the feasibility of the presented laser ion acceleration scheme for the experimental implementation at the currently available petawatt laser facilities.

physics.plasm-ph↗

arXiv2021

Gamma-Ray Flash in the Interaction of a Tightly Focused Single-Cycle Ultraintense Laser Pulse with a Solid Target

We employ the $λ^3$ regime where a near-single-cycle laser pulse is tightly focused, thus providing the highest possible intensity for the minimal energy at a certain laser power. The quantum electrodynamics processes in the course of the interaction of the ultraintense laser with a solid target are studied via three-dimensional particle-in-cell simulations, revealing the generation of copious $γ$-photons and electron-positron pairs. The parametric study on the laser polarisation, target thickness and electron number density shows that the radially polarised laser provides the optimal regime for $γ$-photon generation. By varying the laser power in the range of 1 to 300 petawatt we find the scaling of the laser to $γ$-photon energy conversion efficiency. The laser-generated $γ$-photon interaction with a high-Z target is further studied by using Monte Carlo simulations revealing further electron-positron pair generation and radioactive nuclides creation.

physics.plasm-ph↗

arXiv2020

Reaching the high laser intensity by a radiating electron

Interaction of an electron with the counter-propagating electromagnetic wave is studied theoretically and with the particle-in-cell simulations in the regime of quantum radiation reaction. We find the electron energy in the center of the laser pulse, as it is a key factor for testing the non-linear quantum electrodynamics vacuum properties in the laser-electron collision in the regime of multi-photon Compton scattering and vacuum Cherenkov radiation. With multiparametric analysis we provide the conditions on electron initial energy for reaching the center of the laser pulse and emitting Cherenkov photons.

physics.plasm-ph↗

arXiv2020

Generation of megatesla magnetic fields by intense-laser-driven microtube implosions

A microtube implosion driven by ultraintense laser pulses is used to produce ultrahigh magnetic fields. Due to the laser-produced hot electrons with energies of mega-electron volts, cold ions in the inner wall surface implode towards the central axis. By pre-seeding uniform magnetic fields on the kilotesla order, the Lorenz force induces the Larmor gyromotion of the imploding ions and electrons. Due to the resultant collective motion of relativistic charged particles around the central axis, strong spin current densities of ~ peta-ampere/cm2 are produced with a few tens of nm size, generating megatesla-order magnetic fields. The underlying physics and important scaling are revealed by particle simulations and a simple analytical model. The concept holds promise to open new frontiers in many branches of fundamental physics and applications in terms of ultrahigh magnetic fields.

physics.plasm-ph↗

arXiv2020

Laser-driven generation of collimated quasi-monoenergetic proton beam using double-layer target with modulated interface

Usage of double-layer targets consisting of heavy and light material with modulated interface between them provides a way for laser-driven generation of collimated ion beams. With extensive 2D3V PIC simulations we show that this configuration may result in a development of a relativistic instability with Rayleigh-Taylor and Richtmyer-Meshkov like features. Initially small perturbations are amplified during the laser-target interaction leading to the formation of low-density plasma regions and high-density bunches between them, which are accelerated by the laser radiation pressure as whole compact structures. That results in collimated quasi-monoenergetic proton beam with high average energy. The properties of this proton beam such as its low emittance (one order of magnitude lower compared to that of conventional accelerators) and divergence are discussed. Results are compared with similar acceleration schemes such as double-layer target without corrugation and single-layer target.

physics.plasm-ph↗

arXiv2020

Nonlinear electrodynamics at cylindrical "cumulation" fronts

Converging cylindrical electromagnetic fields in vacuum have been shown (E. I. Zababakhin, M. N. Nechaev, {\it Soviet Physics JETP}, {\bf 6}, 345 (1958)) to exhibit amplitude "cumulation". It was found that the amplitude of self-similar waves increases without bounds at finite distances from the axis on the front of the fields reflected from the cylindrical axis. In the present paper we propose to exploit this cylindrical cumulation process as a possible new path towards the generation of ultra-strong electromagnetic fields where nonlinear quantum electrodynamics (QED) effects come into play. We show that these effects, as described in the long wave-length limit within the framework of the Euler Heisenberg Lagrangian, induce a radius-dependent reduction of the propagation speed of the cumulation front. {Furthermore we compute the $e^+$-$e^-$ pair production rate at the cumulation front and show that the total number of pairs that are generated scales as the sixth power of the field amplitude.

physics.plasm-ph↗

arXiv2020

Towards Laser Ion Acceleration With Holed Targets

Although the interaction of a flat-foil with currently available laser intensities is now considered a routine process, during the last decade emphasis is given to targets with complex geometries aiming on increasing the ion energy. This work presents a target geometry where two symmetric side-holes and a central-hole are drilled into the foil. A study of the various side-holes and central-hole length combinations is performed with 2-dimensional particle-in-cell simulations for polyethylene targets and a laser intensity of 5.2x10^21 W cm^-2. The holed-targets show a remarkable increase of the conversion efficiency, which corresponds to a different target configuration for electrons, protons and carbon ions. Furthermore, diffraction of the laser pulse leads to a directional high energy electron beam, with a temperature of ~40 MeV or seven times higher than in the case of a flat-foil. The higher conversion efficiency consequently leads to a significant enhancement of the maximum proton energy from holed-targets.

physics.plasm-ph↗

arXiv2019

Recoil Effects on Reflection from Relativistic Mirrors in Laser Plasmas

Relativistic mirrors can be realized with strongly nonlinear Langmuir waves excited by intense laser pulses in underdense plasma. On reflection from the relativistic mirror the incident light affects the mirror motion. The corresponding recoil effects are investigated analytically and with particle-in-cell simulations. It is found that if the fluence of the incident electromagnetic wave exceeds a certain threshold, the relativistic mirror undergoes a significant back reaction and splits into multiple electron layers. The reflection coefficient of the relativistic mirror as well as the factors of electric field amplification and frequency upshift of the electromagnetic wave are obtained.

physics.plasm-ph↗

arXiv2019

Electromagnetic Solitons in Quantum Vacuum

In the limit of extremely intense electromagnetic fields the Maxwell equations are modified due to the photon-photon scattering that makes the vacuum refraction index depend on the field amplitude. In presence of electromagnetic waves with small but finite wavenumbers the vacuum behaves as a dispersive medium. We show that the interplay between the vacuum polarization and the nonlinear effects in the interaction of counter-propagating electromagnetic waves can result in the formation of Kadomtsev-Petviashvily solitons and, in one-dimension configuration, of Korteveg-de-Vries type solitons that can propagate over a large distance without changing their shape.

physics.plasm-ph↗