| 1. |
- Efimenko, E., et al.
(författare)
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Extreme plasma states in laser-governed vacuum breakdown
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Triggering vacuum breakdown at laser facility is expected to provide rapid electron-positron p air production for studies in laboratory astrophysics and fundamental physics. However, the density of the produced plasma may cease to increase at a relativistic critical density, when the plasma becomes opaque. Here, we identify the opportunity of breaking this limit using optimal beam configuration of petawatt-class lasers. Tightly focused laser fields allow generating plasma in a small focal volume much less than λ 3 and creating extreme plasma states in terms of density and produced currents. These states can be regarded to be a new object of nonlinear plasma physics. Using 3D QED-PIC simulations we demonstrate a possibility of reaching densities over 10 25 cm -3, which is an order of magnitude higher than expected earlier. Controlling the process via initial target parameters provides an opportunity to reach the discovered plasma states at the upcoming laser facilities.
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| 2. |
- Gonoskov, Arkady, et al.
(författare)
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Anomalous radiative trapping in laser fields of extreme intensity
- 2014
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 113, s. 014801-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that charged particles in a suciently intense standing wave are compressed toward, and oscillate synchronously at, the antinodes of the electric eld. We call this unusualbehaviour `anomalous radiative trapping' (ART). We show using dipole pulses, which oer a pathto increased laser intensity, that ART opens up new possibilities for the generation of radiationand particle beams, both of which are high-energy, directed and collimated. ART also provides a mechanism for particle control in high-intensity quantum-electrodynamics experiments.
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| 3. |
- Gonoskov, Arkady, et al.
(författare)
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Probing Nonperturbative QED with Optimally Focused Laser Pulses
- 2013
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 111:6
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Tidskriftsartikel (refereegranskat)abstract
- We study nonperturbative pair production in intense, focused laser fields called e-dipole pulses. We address the conditions required, such as the quality of the vacuum, for reaching high intensities without initiating beam-depleting cascades, the number of pairs which can be created, and experimental detection of the created pairs. We find that e-dipole pulses offer an optimal method of investigating nonperturbative QED.
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| 4. |
- Sergeev, Alexander M., et al.
(författare)
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Generation of giant attosecond pulses at the plasma surface in the regime of relativistic electronic spring
- 2011
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Ingår i: Diode-Pumped High Energy and High Power Lasers; ELI. - : SPIE - International Society for Optical Engineering. - 9780819486707
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Konferensbidrag (refereegranskat)abstract
- The generation of attosecond pulses with an amplitude greatly exceeding the driving field of an ultrarelativistic laser pulse at oblique irradiation of a solid target is investigated. We develop a universal model of the process, the so-called relativistic electronic spring, which is different from the conventional concept of an oscillating mirror. It follows from the model that there exists a parameter region where the energy conversion from the femto- to the attosecond regime is maximal. Based on the study we propose a new concept of laser pulse interaction with a target having a groove-shaped surface, which opens up the potential to exceed an intensity level of 1026 W/cm(2) and observe effects due to nonlinear quantum electrodynamics with upcoming laser sources.
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| 5. |
- Aurand, B., et al.
(författare)
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Manipulation of the spatial distribution of laser-accelerated proton beams by varying the laser intensity distribution
- 2016
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1089-7674 .- 1070-664X. ; 23:2
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Tidskriftsartikel (refereegranskat)abstract
- We report on a study of the spatial profile of proton beams produced through target normal sheath acceleration using flat target foils and changing the laser intensity distribution on the target front surface. This is done by either defocusing a single laser pulse or by using a split-pulse setup and irradiating the target with two identical laser pulses with variable spatial separation. The resulting proton beam profile and the energy spectrum are recorded as functions of the focal spot size of the single laser pulse and of the separation between the two pulses. A shaping of the resulting proton beam profile, related to both an increase in flux of low-energy protons in the target normal direction and a decrease in their divergence, in one or two dimensions, is observed. The results are explained by simple modelling of rear surface sheath field expansion, ionization, and projection of the resulting proton beam.
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| 6. |
- Bashinov, A. V., et al.
(författare)
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New horizons for extreme light physics with mega-science project XCELS
- 2014
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Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 223:6, s. 1105-1112
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Forskningsöversikt (refereegranskat)abstract
- A short review of the Russian mega-science project XCELS and scientific problems to be solved are presented. We discuss the origin of multi-beam design to attain the highest field magnitude at optimal focusing. Then, we formulate particular physical problems of fundamental interest that can be solved within this project.
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| 7. |
- Bashinov, A. V., et al.
(författare)
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Towards attosecond-scale highly directed GeV gamma-ray sources with multipetawatt-class lasers
- 2017
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Ingår i: Journal of Optics. - : IOP Publishing. - 2040-8978 .- 2040-8986. ; 19:11
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Tidskriftsartikel (refereegranskat)abstract
- We consider a possibility of constructing a gamma-ray source based on the multibeam configuration of a multipetawatt laser system which we simulate using a converging dipole wave. It is shown that such a configuration of fields allows the generation of gamma radiation with narrow directivity of about 1 mrad in the form of pulse trains or isolated pulses on the attosecond timescale. The influence of quantum electrodynamic cascade development on the parameters of generated gamma bursts is studied.
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| 8. |
- Bastrakov, S., et al.
(författare)
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Performance aspects of collocated and staggered grids for particle-in-cell plasma simulation
- 2017
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Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - Cham : Springer International Publishing. - 1611-3349 .- 0302-9743. - 9783319629315 ; 10421, s. 94-100
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Konferensbidrag (refereegranskat)abstract
- We present a computational comparison of collocated and staggered uniform grids for particle-in-cell plasma simulation. Both types of grids are widely used, and numerical properties of the corresponding solvers are well-studied. However, for large-scale simulations performance is also an important factor, which is the focus of this paper. We start with a baseline implementation, apply widely-used techniques for performance optimization and measure their efficacy for both grids on a high-end Xeon CPU and a second-generation Xeon Phi processor. For the optimized version the collocated grid outperforms the staggered one by about 1.5x on both Xeon and Xeon Phi. The speedup on the Xeon Phi processor compared to Xeon is about 1.9x.
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| 9. |
- Bhadoria, Shikha, 1991, et al.
(författare)
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Mapping the power-law decay of high-harmonic spectra from few-cycle laser-solid interactions
- 2022
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- Visible or near infrared light can be manipulated to produce bursts of coherent extreme ultraviolet or x rays via the relativistic high-order harmonic generation process when a laser irradiates a solid plasma target. The intensity of the spectral components of the reflected signal decays with the increase in harmonic order and the efficiency of this non-linear process largely hinges on how prompt this decay is. This is governed by the conditions of the laser-plasma interaction for which various models have been proposed. At relativistic intensities, a spectrum exhibiting a power-law decay with an exponent of 8/3 or 4/3 is often stated. Here, we analyze the dependence of this exponent on interaction parameters, including the angle of incidence, the carrier envelope phase, intensity of the laser, and the pre-plasma length, and discuss opportunities for optimization. Our simulations show that, rather than there being one universal exponent, the spectral decay is a continuous function of the laser-plasma interaction parameters.
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| 10. |
- Blackburn, Tom, 1989, et al.
(författare)
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Relativistically intense XUV radiation from laser-illuminated near-critical plasmas
- 2018
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Ingår i: Physical Review A. - 2469-9934 .- 2469-9926. ; 98:2
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Tidskriftsartikel (refereegranskat)abstract
- Pulses of extreme ultraviolet (XUV) light, with wavelengths between 10 and 100nm, can be used to image and excite ultrafast phenomena such as the motion of atomic electrons. Here we show that the illumination of plasma with near-critical electron density may be used as a source of relativistically intense XUV radiation, providing the means for novel XUV-pump-XUV-probe experiments in the nonlinear regime. We describe how the optimal regime may be reached by tailoring the laser-target interaction parameters and by the presence of preplasma. Our results indicate that currently available laser facilities are capable of producing XUV pulses with duration ∼10fs, brilliance in excess of 1023photons/s/mm2/mrad2 (0.1% bandwidth), and intensity Iλ21019Wcm-2μm2.
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