Simple scalings for various regimes of electron acceleration in surface plasma waves

Riconda, C.; Raynaud, M.; Vialis, Théo; Grech, M.

doi:10.1063/1.4923443

Cited by 32 publications

(50 citation statements)

References 34 publications

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“…The experimental results, with large amounts of electrons being accelerated to energies of the order of U f , suggest that self-injection is quite efficient (although it delivers a broad spectrum). This is also supported by the study of Riconda et al 41 based on the numerical solution of test particle motion in the fields of a high-amplitude SP. In particular, injection is provided to a large extent (in the laboratory frame) by the nonlinear magnetic force F y = −ev x B z /c along the SP propagation direction.…”

Section: A Experimental Observationsupporting

confidence: 68%

Extreme high field plasmonics: Electron acceleration and XUV harmonic generation from ultrashort surface plasmons

et al. 2019

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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 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 collimated in a near-tangent direction. By the use of a suitable blazed grating, the bunch charge can be increased up to ≈660 picoCoulomb. Intense XUV high harmonics (HHs) diffracted by the grating are observed when a plasma with sub-micrometer scale is produced at the target surface by a controlled prepulse. When the SP is excited, the HHs are strongly enhanced in a direction quasi-parallel to the electrons. Simulations suggest that the HHs are boosted by nanobunching in the SP field of the electrons which scatter the laser field. Besides the static and dynamic tailoring of the target density profile, further control of electron and HH emission might be achieved by changing the SP duration using a laser pulse with rotating wavefront. This latter technique may allow to produce nearly single-cycle SPs.

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Section: A Experimental Observationsupporting

confidence: 68%

Extreme high field plasmonics: Electron acceleration and XUV harmonic generation from ultrashort surface plasmons

et al. 2019

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“…As there are several laser absorption mechanisms in overdense plasmas, such as the generation of surface plasma waves (SPW) [13,15,16,29,[31][32][33][34][35], resonant absorption, vacuum heating or J×B heating [36][37][38], one can use nanostructures with properties especially suited to enhance a particular absorption mechanism. Our aim is to optimize the acceleration of electrons in the vacuum gaps of a periodic structure, so-called vacuum heating [17,21,27].…”

Section: Introductionmentioning

confidence: 99%

Table-top laser-based proton acceleration in nanostructured targets

et al. 2017

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The interaction of ultrashort, high intensity laser pulses with thin foil targets leads to ion acceleration on the target rear surface. To make this ion source useful for applications, it is important to optimize the transfer of energy from the laser into the accelerated ions. One of the most promising ways to achieve this consists in engineering the target front by introducing periodic nanostructures. In this paper, the effect of these structures on ion acceleration is studied analytically and with multidimensional particle-in-cell simulations. We assessed the role of the structure shape, size, and the angle of laser incidence for obtaining the efficient energy transfer. Local control of electron trajectories is exploited to maximize the energy delivered into the target. Based on our numerical simulations, we propose a precise range of parameters for fabrication of nanostructured targets, which can increase the energy of the accelerated ions without requiring a higher laser intensity.

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“…In these distributions deduced from the PIC simulations we observe a clear cutoff like behavior in the electron momentum p, particularly pronounced at times ω 0 t <500 (corresponding to real Cut-off like behavior for similar configuration has been systematically observed both in Maxwell-Vlasov and PIC simulations. 25,26,[28][29][30][33][34][35] The cutoff in the distribution means that electrons could not be accelerated beyond this value in p, or, the probability to find electrons beyond a certain p-value drops to zero. It means that electrons cannot attain momenta p > p max .…”

Section: Application To the Simulationmentioning

confidence: 99%

“…It has clearly been seen in simulations [25][26][27][28][29][30][33][34][35] that distribution functions of laser-accelerated electrons show an upper bound in the particle momentum p/(m e c). While the nature of this upper bound is difficult to identify in Particle-in-Cell (PIC) simulations, because of the limited number of particles in the tail of the distribution, [25][26][27]30,[33][34][35] it is striking that Vlasov-Maxwell simulations bring to evidence non-Gaussian statistics and cutoff behavior for the electron distribution. 28,29 From such studies it follows that the upper bound in the spectrum of the accelerated electrons scales with the laser intensity, and depends furthermore on the incidence angle, the density gradient of the vacuum plasma interface, and on the complexity of the surface structure.…”

Section: Introductionmentioning

confidence: 99%

On the non-thermal nature of distributions of electrons accelerated by high intensity lasers at the vacuum-plasma interface

et al. 2019

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The distribution function of electrons accelerated by intense laser pulses at steep vacuumplasma interfaces is investigated by using Fokker-Planck equation and methods from extreme statistics. The energy spectrum of electrons penetrating into the dense plasma after being accelerated at the interface and in the pre-plasma shows systematically cutoff-like decrease in the momentum component p x /m e c along the laser propagation axis. While the distribution associated to the kinetic energy spectrum (E kin ) is often approximated by a thermal distribution, F(E kin ) ∝ exp(−E kin /T h ), with a hot particle temperature T h , the nature of the distribution close to the cutoff is clearly non-thermal. Electron distributions are analyzed here from two-dimensional Particle-in-Cell simulations. Via a comparison with solutions derived from a Fokker-Planck equation and based on Chirikov's standard map models, we find that the electron distributions show a clear signature of stochastic heating, due to repeated acceleration in the standing wave in the pre-plasma. Further analysis of the solutions to the Fokker-Planck equation allows us to describe the cutoff seen in the momentum p of the distributions F(p), which can be expressed as a function of time τ in the form F(p, τ) ∝ [(p max − p)/δ p] exp −2p 3 /9τ , portraying a time-dependent cutoff at p → p max . This implies that the energetic tail of the distribution belongs to the maximum domain of attraction of the Weibull law, which means that the probability to find highenergy electrons varies abruptly near p max . The variance of physical observables sensitive to the high-energy tail is consequently considerably higher than when assuming thermal distribution. a)

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Simple scalings for various regimes of electron acceleration in surface plasma waves

Cited by 32 publications

References 34 publications

Extreme high field plasmonics: Electron acceleration and XUV harmonic generation from ultrashort surface plasmons

Extreme high field plasmonics: Electron acceleration and XUV harmonic generation from ultrashort surface plasmons

Table-top laser-based proton acceleration in nanostructured targets

On the non-thermal nature of distributions of electrons accelerated by high intensity lasers at the vacuum-plasma interface

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