Analytic theory of relativistic self-focusing for a Gaussian light beam entering a plasma: Renormalization-group approach

Kovalev, V. F.; Bychenkov, V. Yu.

doi:10.1103/physreve.99.043201

Cited by 24 publications

(23 citation statements)

References 43 publications

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“…The corresponding nonlinear structure looks like an empty cavity of pulse length with an electrostatic field filled with a laser field (a "laser bullet"). The considered relativistic laser pulse satisfies the condition of complete electron cavitation immediately at the entrance of the light into the target, which supports almost the same pulse radius over entire propagation length until pulse depletion in accordance with the most advanced theory, where self-focusing is associated with plasma nonlinearities due to both relativistic electron mass variation and relativistic charge displacement [20]. Acceleration of electrons in laser bullet occurs as a combination of direct laser acceleration and electrostatic wake acceleration with a stochastic feature.…”

Section: Discussionsupporting

confidence: 78%

“…( 1), where α = √ 2 in the paraxial ray approximation with a simplified relativistic nonlinearity [19]. We note that the condition of complete electron cavitation immediately at the entrance of the light beam into the target also requires the same pulse radius in accordance with the most advanced theory, where self-focusing is associated with plasma nonlinearities due to both relativistic electron mass variation and relativistic charge displacement [20].…”

Section: Self-trapping Regimementioning

confidence: 59%

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Effective production of gammas, positrons, and photonuclear particles from optimized electron acceleration by short laser pulses in low-density targets

2019

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Electron acceleration has been optimized based on 3D PIC simulations of a short laser pulse interacting with low-density plasma targets to find the pulse propagation regime that maximizes the charge of high-energy electron bunches. This regime corresponds to laser pulse propagation in a self-trapping mode where the diffraction divergence is balanced by the relativistic nonlinearity such that relativistic self-focusing on the axis does not happen and the laser beam radius stays unchanged during pulse propagation in a plasma over many Rayleigh lengths. Such a regime occurs for a nearcritical density if the pulse length considerably exceeds both the plasma wavelength and the pulse width. Electron acceleration occurs in a traveling cavity filled with a high-frequency laser field and a longitudinal electrostatic single-cycle field ("self-trapping regime"). Monte Carlo simulations demonstrated a high electron yield that allows an efficient production of gamma radiation, electronpositron pairs, neutrons, and even pions from a catcher-target.

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Section: Discussionsupporting

confidence: 78%

Section: Self-trapping Regimementioning

confidence: 59%

Effective production of gammas, positrons, and photonuclear particles from optimized electron acceleration by short laser pulses in low-density targets

2019

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“…The influence of both mechanisms on the propagation mode for a relativistic laser beam has been discussed in detail in various papers [14,[16][17][18][19] and monographs [20,21]. A recent work [11] gives an analytical description of a self-focusing structure formation for a laser beam having a given form of the radial intensity distribution at the plasma entrance which can be plasma-vacuum interface, as in our PIC model. This work which includes the mentioned relativistic nonlinearities has taken an important step towards the solution of the boundary-value problem for the incident Gaussian light beam, that is exactly what corresponds to PIC simulations with parameter R inside plasma.…”

Section: Self-trapping Regimementioning

confidence: 99%

“…This matching condition is shown to be the condition for a self-trapping regime of relativistic self-channeling, which we prove in Sec. IV using a recently developed theory [11]. We discuss the results and conclusions in Sec.…”

Section: Introductionmentioning

confidence: 95%

Generation of high-charge electron beam in a subcritical-density plasma through laser pulse self-trapping

Bychenkov¹,

Lobok²,

Kovalev³

et al. 2019

Plasma Phys. Control. Fusion

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To maximize the charge of a high-energy electron beam accelerated by an ultra-intense laser pulse propagating in a subcritical plasma, the pulse length should be longer than both the plasma wavelength and the laser pulse width, which is quite different from the standard bubble regime.In addition, the laser-plasma parameters should be chosen to produce the self-trapping regime of relativistic channeling, where the diffraction divergence is balanced by the relativistic nonlinearity such that the laser beam radius is unchanged during pulse propagation in a plasma over many Rayleigh lengths. The condition for such a self-trapping regime is the same as what was empirically found in several previous simulation studies in the form of the pulse width matching condition.Here, we prove these findings for a subcritical plasma, where the total charge of high-energy electrons reaches the multi-nC level, by optimization in a 3D PIC simulation study and compare the results with an analytic theory of relativistic self-focusing. A very efficient explicitly demonstrated generation of high-charge electron beams opens a way to a high-yield production of gammas, positrons, and photonuclear particles.

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“…The condition, Eq. ( 1), corresponds to the self-trapping regime of relativistic self-focusing (see, for example, [22,23]), which occurs for the laser pulses with the focal radius at the plasma entrance being close to the self-consistent radius. The initial laser pulse radius approaching the value Eq.…”

mentioning

confidence: 99%

Bright synchrotron radiation from relativistic self-trapping of a short laser pulse in near-critical density plasma

Lobok,

Andriyash,

Vais

et al. 2021

Preprint

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In a dense gas plasma a short laser pulse propagates in relativistic self-trapping mode, which enables effective conversion of laser energy to the accelerated electrons. This regime sustains effective loading which maximizes the total charge of the accelerating electrons, that provides a large amount of betatron radiation. The 3D particle-in-cell simulations demonstrate how such regime triggers X-ray generation with 0.1-1 MeV photon energies, low divergence, and high brightness. It is shown that a 135 TW laser can be used to produce 3 × 10 10 photons of > 10 keV energy and a 1.2 PW laser makes it possible generating about 10 12 photons in the same energy range. The laser-togammas energy conversion efficiency is up to 10 −4 for the high-energy photons, ∼ 100 keV, while the conversion efficiency to the entire keV-range x-rays is estimated to be a few tenths of a percent.

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Analytic theory of relativistic self-focusing for a Gaussian light beam entering a plasma: Renormalization-group approach

Cited by 24 publications

References 43 publications

Effective production of gammas, positrons, and photonuclear particles from optimized electron acceleration by short laser pulses in low-density targets

Effective production of gammas, positrons, and photonuclear particles from optimized electron acceleration by short laser pulses in low-density targets

Generation of high-charge electron beam in a subcritical-density plasma through laser pulse self-trapping

Bright synchrotron radiation from relativistic self-trapping of a short laser pulse in near-critical density plasma

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