Self-focusing up to the incident laser wavelength by an appropriate density ramp

Sadighi‐Bonabi, R.; Moshkelgosha, Masoume

doi:10.1017/s0263034611000589

Cited by 10 publications

(7 citation statements)

References 41 publications

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“…Equation (19) in terms of the beam width parameter for the super-Gaussian laser beams and equation (20) for the Gaussian laser beams are solved numerically using second-order finite difference method with step size of 0.03 and the initial conditions as f B = 1 and ∂fB ∂ς = 0 at ς = 0. Numerical methods to solving nonlinear equations have proved to be effective in different areas [29,30].…”

Section: Resultsmentioning

confidence: 99%

“…The diffraction divergence term is the first term on the right hand side of equation (19), and nonlinear refraction due to relativistic nonlinearity and ponderomotive nonlinearity are respectively represented by the second and third terms of this equation. The diffraction divergence and nonlinear refraction processes compete with each other and cause self-focusing/defocusing of the laser beam.…”

Section: Development Of Modelmentioning

confidence: 99%

“…They have considered plasma ramp density profile as tangent profile and used the paraxial formulation. Bonabi and Moshkelgosha [19] have extended the same theory using a new density profile. They found the propagation of high-power laser pulse over many Rayleigh lengths.…”

Section: Introductionmentioning

confidence: 97%

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Self-focusing and defocusing phenomena of super-Gaussian laser beams in plasmas carrying density gradient

Devi¹,

Malik²

2023

J. Opt.

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Considering nonlinearities due to relativistic mass variation and ponderomotive force driven depression in the electron density, a model is developed for the self-focusing of a super-Gaussian laser beam in inhomogeneous plasmas. Since paraxial ray approximation is not appropriate for the beams of super-Gaussian profile, the formulation is developed based on the moment theory. To have an in-depth understanding of self-focusing and defocusing phenomena and to develop generalized treatment, three different types of plasma density profiles namely linear, tangent and exponential density profiles, are considered and the results are compared. Due to the saturating nature of nonlinear permittivity with laser intensity, the beam is found to undergo periodic focusing because of competition between the diffraction divergence and nonlinear self-focusing effects. The ponderomotive nonlinearity enhances the self-focusing. As the super-Gaussian beam moves into higher density plasma region up to several Rayleigh lengths, stronger self-focusing is achieved and the value of minimum spot size decreases.

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Section: Resultsmentioning

confidence: 99%

Section: Development Of Modelmentioning

confidence: 99%

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Self-focusing and defocusing phenomena of super-Gaussian laser beams in plasmas carrying density gradient

Devi¹,

Malik²

2023

J. Opt.

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“…Since the invention of chirped pulse amplification, the construction of compact ultra-intense and ultra-short laser pulses has become feasible. Propagation of such laser pulses has been investigated in various plasma conditions (Wang et al, 2011;Sadighi-Bonabi et al, 2011) resulted in generation of mono-energetic electrons (Faure et al, 2004;Yazdanpanah et al, 2014) protons and ions (Hegelich et al, 2006;Yazdani et al, 2009;Hora et al, 2012) and X-rays (Nikzad et al, 2012;Shirozhen et al, 2014). Laser based ion acceleration is highly attractive due to its potential applications, including fast ignition (Roth et al, 2001), proton radiography (Borghesi et al, 2006), and so on.…”

Section: Introductionmentioning

confidence: 99%

Enhanced laser ion acceleration with a multi-layer foam target assembly

et al. 2014

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Interaction of a linearly polarized Gaussian laser pulse (at relativistic intensity of 2.0 × 1020 Wcm−2) with a multi-layer foam (as a near critical density target) attached to a solid layer is investigated by using two-dimensional particle-in-cell simulation. It is found that electrons with longitudinal momentum exceeding the free electrons limit of meca02/2 so-called super-hot electrons can be produced when the direct laser acceleration regime is fulfilled and benefited from self-focusing inside of the subcritical plasma. These electrons penetrate easily through the target and can enhance greatly the sheath field at the rear, resulting in a significant increase in the maximum energy of protons in target normal sheath acceleration regime. The results indicate that the maximum proton energy is enhanced by 2.7 times via using an assembled target arrangement compared to a bare solid target. Furthermore, by demonstration of this assembly, the maximum proton energy is improved beyond the optimum amount achieved by a two-layer target proposed by Sgattoni et al. (2012).

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“…The propagation of such intense short laser pulses has been investigated for various plasma conditions [2][3][4][5]. Production of energetic particle beams, such as quasi-monoenergetic electrons and ion blocks, has been reported [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Investigation by simulation of X-ray beams produced via interactions of suitable quasi-monoenergetic electrons with solid targets

Nikzad

Ehtesami-sarabi

2014

Journal of the Korean Physical Society

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X-ray generation by interactions of quasi-monoenergetic electrons with solid lead targets is studied. Various electron energy spectra generated by a laser-plasma accelerator are employed to generate Bremsstrahlung and characteristic X-rays. These X-ray photons are simulated by using the Monte Carlo N-Particle Transport Code (MCNP). The present work is mainly focused on exploring the influence of two parameters of the electron profile, the peak energy (Ep) and the pulse width (ΔE), on X-ray generation. If an electron source with higher Ep and smaller ΔE is used, the efficiency of X-ray creation is found to be increased in thick targets. However, in thin samples, the electron profile with lower Ep and larger ΔE dominates.

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Self-focusing up to the incident laser wavelength by an appropriate density ramp

Cited by 10 publications

References 41 publications

Self-focusing and defocusing phenomena of super-Gaussian laser beams in plasmas carrying density gradient

Self-focusing and defocusing phenomena of super-Gaussian laser beams in plasmas carrying density gradient

Enhanced laser ion acceleration with a multi-layer foam target assembly

Investigation by simulation of X-ray beams produced via interactions of suitable quasi-monoenergetic electrons with solid targets

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