Relativistic and ponderomotive self-focusing at laser–plasma interaction

Osman, Frederick; Castillo, R.; Hora, Heinrich

doi:10.1017/s0022377898007417

Cited by 63 publications

(24 citation statements)

References 3 publications

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“…For the 0.21 TW laser power, the Z = 13 copper ions are expected to have a maximum energy of 22.6 MeV (Hora et al 2002b) in agreement with the numerous measurements of several groups in the past. The final result for the maximum ion energy ε trans after relativistic self-focusing (Hora 1975;Jones et al 1982;Häuser et al 1992;Osman et al 1999;, fitting with all the long years of observations (Haseroth et al 1996) with laser pulses longer than 100 ps, was found to be dependent on the laser power P , the ion charge Z and the focused beam Number of (integrated signal) emitted fast ions and thermal ions from a perpendicular irradiated copper target at neodymium glass irradiation for 1.2 ps pulses depending on the laser pulse energy focused to a 30 wavelength diameter beam at the target surface with suppression of a prepulse by 10 8 for a time less then 100 ps before the main pulse arrived. During the last 100 ps the contrast ratio was about 10 4 (Badziak et al 1999(Badziak et al , 2003Hora, Badziak et al 2002a). diameter δ in multiples of the laser vacuum wave length (larger than 0.6) as in the following relation:…”

Section: Experiments Confirming the Skin Layer Interactionmentioning

confidence: 99%

Computations for nonlinear force driven plasma blocks by picosecond laser pulses for fusion

Chen

Osman²,

Hora

et al. 2005

J. Plasma Phys.

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The concept of the fast ignitor for laser fusion has led to some modifications in applying petawatt-picosecond (PW-ps) laser-produced high intensity particle beams to ignite deuterium-tritium (DT) fuel. Some very anomalous measurements of ion emission from targets irradiated by picosecond laser pulses led to the development of a skin depth interaction scheme where a defined control of prepulses is necessary. Based on these experimental facts, we have applied a onedimensional two-fluid hydrodynamic code to understand how the nonlinear ponderomotive force generates two plasma blocks, one moving against the laser light (ablation) and the other moving into the target. This compressed block produces an ion current density of above 10 11 A cm −2 and an ion energy of about 100 keV. This may be a rather promising option to use PW-ps laser pulses for igniting fusion in solid density DT fuel, realizing very high gain controlled fusion reactions.

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Section: Experiments Confirming the Skin Layer Interactionmentioning

confidence: 99%

Computations for nonlinear force driven plasma blocks by picosecond laser pulses for fusion

Chen

Osman²,

Hora

et al. 2005

J. Plasma Phys.

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“…In such a case the nonlinearity in the dielectric function occurs is caused by the electron mass variation due to large laser irradiance and the change in electron density as a consequence of the ponderomotive force. Very few studies on self focusing [35,36] and cross focusing [37] of the laser beams have been made, incorporating the combined effect of relativistic and ponderomotive nonlinearities. Further the effect of an ultra intense laser pulse on the propagation of an electron plasma wave has been analyzed by Kumar et al [38] in the relativistic-ponderomotive regime.…”

Section: Introductionmentioning

confidence: 99%

Focusing of Dark Hollow Gaussian Electromagnetic Beams in a Plasma With Relativistic-Ponderomotive Regime

MIshra¹,

Mishra²

2009

PIER B

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Abstract-This paper presents a theoretical model for the propagation of a hollow Gaussian electromagnetic beam [HGB], propagating in a plasma with dominant relativistic-ponderomotive nonlinearity. A paraxial like approach has been invoked to understand the nature of propagation; in this approach all the relevant parameters correspond to a narrow range around the irradiance maximum of the HGB. The critical curves for the propagation of various order HGBs have been discussed, and the dependence of the beam width parameter on distance of propagation has been evaluated for three typical cases viz. of steady divergence, oscillatory divergence and self focusing of the HGB.

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“…However, in our parameter range with lower laser intensity, the relativistic contribution is entirely negligible. 21 The related periodic focusing and defocusing may be typical for an integrable nonlinear paraxial equation 22 with an appropriate initial condition. For I 0 = 150I cr [see point B in Fig.…”

Section: Numerical Simulations and Nonlinear Dynamicsmentioning

confidence: 99%

Propagation of femtosecond terawatt laser pulses in N2 gas including higher-order Kerr effects

Huang

Zhou

2012

AIP Advances

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Propagation characteristic of femtosecond terawatt laser pulses in N2 gas with higher-order Kerr effect (HOKE) is investigated. Theoretical analysis shows that HOKE acting as Hamiltonian perturbation can destroy the coherent structure of a laser field and result in the appearance of incoherent patterns. Numerical simulations show that in this case two different types of complex structures can appear. It is found that the high-order focusing terms in HOKE can cause continuous phase shift and off-axis evolution of the laser fields when irregular homoclinic orbit crossings of the field in phase space take place. As the laser propagates, small-scale spatial structures rapidly appear and the evolution of the laser field becomes chaotic. The two complex patterns can switch between each other quasi-periodically. Numerical results show that the two complex patterns are associated with the stochastic evolution of the energy contained in the higher-order shorter-wavelength Fourier modes. Such complex patterns, associated with small-scale filaments, may be typical for laser propagation in a HOKE medium

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Relativistic and ponderomotive self-focusing at laser–plasma interaction

Cited by 63 publications

References 3 publications

Computations for nonlinear force driven plasma blocks by picosecond laser pulses for fusion

Computations for nonlinear force driven plasma blocks by picosecond laser pulses for fusion

Focusing of Dark Hollow Gaussian Electromagnetic Beams in a Plasma With Relativistic-Ponderomotive Regime

Propagation of femtosecond terawatt laser pulses in N2 gas including higher-order Kerr effects

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