Experimental Observation of Electrons Accelerated in Vacuum to Relativistic Energies by a High-Intensity Laser

Malka, G.; Lefebvre, E.; Miquel, J.L.

doi:10.1103/physrevlett.78.3314

Cited by 301 publications

(178 citation statements)

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“…The second excursion from the exact solution [2] results in the novel idea of vacuum laser acceleration. In this case Amatuni elaborated on the concept of electron quiver expulsion from the laser focus, demonstrated in experiment [7]. It has been shown that when laser power is above the threshold value [8], quiver amplitude of the electron exceeds the radius of the focal spot of a Gaussian laser beam and the electron is scattered away from the focus.…”

Section: -4402͞00͞3(5)͞059002mentioning

confidence: 99%

Response to “Comment on `Nonlinear Compton scattering and electron acceleration in interfering laser beams'”

Pogorelsky

2000

Phys. Rev. ST Accel. Beams

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Response is made to Y. I. Salamin's preceding Comment [Phys. Rev. ST Accel. Beams 3, 059001 (2000)]. We confirm the areas of applicability of the original and Salamin's general solutions and discuss new applications of the developed formalism.PACS numbers: 13.60. Fz, 14.60.Cd, 03.65.Ge, 41.20.Jb In his Comment, Salamin [1] proposes a generalized format for the exact solution of the equations of motion of relativistic electrons in the field of two plane electromagnetic waves attained by Amatuni and Pogorelsky [2]. The revised form of the solution, otherwise equivalent to one derived in [2], facilitates an explicit treatment of the problem of two copropagating electromagnetic waves that are different in frequency. As soon as the equivalency of the revised solution [given by Eqs. (4), (14)- (16) since the initial purpose of their study was to uncover the phase sensitive effects (x-ray radiation and the electron energy modulation) occurring when the relativistic electron passes a standing electromagnetic wave.A practical motivation for the Amatuni and Pogorelsky study [2] was to develop a novel tool to diagnose electron microbunches grouped to laser wavelength. Such microbunching is essential for attaining a monoenergetic regime of direct electron acceleration in laser field. Microbunches grouped to the 10 mm period have been produced via an inverse free-electron laser process and demonstrated by the coherent transition radiation method at the BNL accelerator test facility (ATF) [3]. The first attempt to phase such "dotted" electron beams into the inverse Cherenkov laser accelerator module is under way at the ATF [4,5].As stated in the preceding paragraph, the goal of developing a novel method of microbunch diagnostics was accomplished by deriving phase sensitive expressions for intensity of the nonlinear component of electron Thomson scattering and for electron energy modulation [2].Needless to say, the solution of the general equations of the electron motion in interfering waves, in addition to the standing wave case, allows excursions to other two-wave combinations. Among them is the problem considered in [1] of a relativistic electron exposed to copropagating waves of different frequency that is applicable to the so-called vacuum beat wave accelerator (VBWA) [6].Not undermining the validity of the solutions attained in [1] and [2], the author wishes to use this occasion to comment on the applicability of the developed formalism to real world situations.Both of the referenced papers address the solution of the electron motion in interfering plane waves. Furthermore, in order to obtain the net acceleration effect in copropagating waves or phasing effects in counterpropagating waves (standing wave) the electron-laser interaction length shall be terminated by some sort of screen or cavity mirror. Both assumptions (plane waves and cavities) look impractical when the laser field is appreciably strong to induce relativistic quiver electron motion. Indeed, ultrahigh electromagnetic field, attractive for novel metho...

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Section: -4402͞00͞3(5)͞059002mentioning

confidence: 99%

Response to “Comment on `Nonlinear Compton scattering and electron acceleration in interfering laser beams'”

Pogorelsky

2000

Phys. Rev. ST Accel. Beams

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“…[22]. Omitting these components leads to incorrect trajectories (as in [12,30]), by artificially restricting all forces to the polarization plane. We used PIC simulations to determine the reflectivity of the plasma mirror, which was about 70% in our conditions.…”

Section: Modelmentioning

confidence: 99%

Vacuum laser acceleration of relativistic electrons using plasma mirror injectors

et al. 2015

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Accelerating particles to relativistic energies over very short distances using lasers has been a long standing goal in physics. Among the various schemes proposed for electrons, vacuum laser acceleration has attracted considerable interest and has been extensively studied theoretically because of its appealing simplicity: electrons interact with an intense laser field in vacuum and can be continuously accelerated, provided they remain at a given phase of the field until they escape the laser beam. But demonstrating this effect experimentally has proved extremely challenging, as it imposes stringent requirements on the conditions of injection of electrons in the laser field. Here, we solve this long-standing experimental problem for the first time by using a plasma mirror to inject electrons in an ultraintense laser field, and obtain clear evidence of vacuum laser acceleration.With the advent of PetaWatt class lasers, this scheme could provide a competitive source of very high charge (nC) and ultrashort relativistic electron beams.1 arXiv:1511.05936v1 [physics.plasm-ph] 18 Nov 2015Femtosecond lasers currently achieve light intensities at focus that far exceed 10 18 W/cm 2 at near infrared wavelengths [1]. One of the great prospects of these extreme intensities is the laser-driven acceleration of electrons to relativistic energies within very short distances.At present, the most advanced scheme consists of using ultraintense laser pulses to excite large amplitude wakefields in underdense plasmas, providing extremely high accelerating gradients in the order of 100 GV/m [2]. However, over the past decades, the direct acceleration of electrons by light in vacuum has also attracted considerable interest and has been extensively studied theoretically [3][4][5][6][7][8][9][10][11]. These investigations have been driven by the fundamental interest of this most elementary interaction, and by its potential for extreme electron acceleration through electric fields of > 10's TV/m that ultraintense laser pulses provide.The underlying idea is to inject free electrons into an ultraintense laser field so that they always remain within a given half optical cycle of the field, where they constantly gain energy until they leave the focal volume. 1D Analytical calculations [3] show that for relativistic electrons, the maximum energy gain from this process is ∆E ∝ mc 2 γ 0 a 2 0 , where γ 0 is the electron initial Lorentz factor, and a 0 is the normalized laser vector potential, m the electron mass, and c the vacuum light velocity. Reaching high energy gains thus requires high initial energies γ 0 1 and/or ultrahigh laser amplitudes (a 0 1).In contrast with the large body of theoretical work published on this vacuum laser acceleration (VLA) of electrons to relativistic energies, experimental observations have largely remained elusive [12][13][14][15][16][17] -sometimes even controversial [18,19]-and have so far not demonstrated significant energy gains. This is because VLA occurs efficiently only for electrons injected in t...

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“…Instead of using the plasma wave to accelerate charged particles, there exists the possibility of direct acceleration of electrons by an intense laser pulse as demonstrated by a recent experiment (Malka et al 1997). Electrons injected at an angle with respect to the direction of propagation of the laser pulse were accelerated to MeV energies.…”

Section: Introductionmentioning

confidence: 99%

Particle acceleration by electromagnetic waves

Bingham

2008

Phil. Trans. R. Soc. A.

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We consider the symmetry in the interaction of photons and electrons, which has led to a common description of electron and photon accelerations; effects such as photon Landau damping arise naturally from such a treatment. Intense electromagnetic waves can act as a photon mirror to charged particles. The subsequent acceleration is equivalent to the photon pulse accelerating electrons. During the interaction or reflection process, the charged particle can emit bursts of radiation similar to the radiation emitted from the particles during wave breaking of plasma waves.

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Experimental Observation of Electrons Accelerated in Vacuum to Relativistic Energies by a High-Intensity Laser

Cited by 301 publications

References 10 publications

Response to “Comment on `Nonlinear Compton scattering and electron acceleration in interfering laser beams'”

Response to “Comment on `Nonlinear Compton scattering and electron acceleration in interfering laser beams'”

Vacuum laser acceleration of relativistic electrons using plasma mirror injectors

Particle acceleration by electromagnetic waves

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