scholarly journals Pulse-compression and self-focusing of Gaussian laser pulses in plasma having relativistic–ponderomotive nonlinearity

2017 ◽  
Vol 35 (3) ◽  
pp. 429-436 ◽  
Author(s):  
S. Kumar ◽  
P.K. Gupta ◽  
R.K. Singh ◽  
S. Sharma ◽  
R. Uma ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Pulse Compression ◽  
Group Velocity Dispersion ◽  
Beam Width ◽  
Laser Pulses ◽  
Oscillatory Behavior ◽  
Intense Laser ◽  
Beam Radius ◽  
Self Focusing ◽  
Ponderomotive Nonlinearity

AbstractThe mathematical model for the propagation of intense laser pulse in a plasma having Gaussian profile is investigated. The model has been formulated considering that the relativistic–ponderomotive nonlinearity dominates over other nonlinearities in the plasma. Model equation for self-compression and self-focusing properties of the laser pulse has been set up and solved by both semi-analytical and numerical methods. The result indicates that due to the effect of group velocity dispersion, diffraction of the laser pulse and the nonlinearity of medium, the pulse width parameter as well as beam width parameter of pulse gets focused at a different normalized distance, and hence the normalized intensity is also deferred at those points. Numerical simulation shows an oscillatory behavior of intensity during propagation in the plasma either having minimum beam radius (r0) or having minimum pulse duration (t0) depending on the normalized distance.

scholarly journals X-ray spectroscopy observation of fast ions generation in plasma produced by short low-contrast laser pulse irradiation of solid targets

2007 ◽  
Vol 25 (2) ◽  
pp. 267-275 ◽  
Author(s):  
A.YA. Faenov ◽  
A.I. Magunov ◽  
T.A. Pikuz ◽  
I. YU. Skobelev ◽  
S.V. Gasilov ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Laser Intensity ◽  
Laser Pulses ◽  
Intense Laser ◽  
Low Contrast ◽  
X Ray ◽  
Fast Ions ◽  
Self Focusing ◽  
Short Laser Pulses ◽  
Charged Ions

X-ray spectra of plasma produced by the interaction of Ti:Sa laser pulses (duration from 60 fs to 1 ps, and energy from 15 mJ to 128 mJ) with foil and solid Teflon and AL targets are investigated. It is shown experimentally and theoretically that the use of low contrast (10−2 – 10−4) short laser pulses, essentially promotes the conditions for generation of fast multi-charged ions. This effect is caused by self-focusing of the main laser pulse in a preplasma produced by intense laser prepulses. Modeling of the observed spectral line shape gives evidence of a considerable (about 3%) amount of multi-charged He-like F ions with energy E ∼ 1 MeV at rather low values of laser intensity IL ≈ 6 × 1016 W cm−2.

scholarly journals Jitter-free 40-fs 375-keV electron pulses directly accelerated by an intense laser beam and their application to direct observation of laser pulse propagation in a vacuum

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shunsuke Inoue ◽  
Shuji Sakabe ◽  
Yoshihide Nakamiya ◽  
Masaki Hashida
Keyword(s):  
Laser Pulse ◽  
Electric Fields ◽  
Pulse Compression ◽  
Permanent Magnets ◽  
Pulse Propagation ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Intense Laser ◽  
Electron Pulse ◽  
Electron Pulses

AbstractWe report the generation of ultrashort bright electron pulses directly driven by irradiating a solid target with intense femtosecond laser pulses. The duration of electron pulses after compression by a phase rotator composed of permanent magnets was measured as 89 fs via the ponderomotive scattering of electron and laser pulses, which were almost at the compression limit due to the dispersion of the electron optics. The electron pulse compression system consisting of permanent magnets enabled extremely high timing stability between the laser pulse and electron pulse. The long-term RMS arrival time drift was below 14 fs in 4 h, which was limited by the resolution of the current setup. Because there was no time-varying field to generate jitter, the timing jitter was essentially reduced to zero. To demonstrate the capability of the ultrafast electron pulses, we used them to directly visualize laser pulse propagation in a vacuum and perform 2D mapping of the electric fields generated by low-density plasma in real time.

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

2011 ◽  
Vol 29 (4) ◽  
pp. 453-458 ◽  
Author(s):  
R. Sadighi-Bonabi ◽  
M. Moshkelgosha
Keyword(s):  
Beam Width ◽  
Laser Pulses ◽  
Laser Wavelength ◽  
Intense Laser ◽  
Uniform Density ◽  
Density Profiles ◽  
Self Focusing ◽  
High Intensity Laser ◽  
Unmagnetized Plasma ◽  
Intensity Laser

AbstractThis work is devoted to improving relativistic self-focusing of intense laser beam in underdense unmagnetized plasma. New density profiles are introduced to achieve beam width parameter up to the wavelength of the propagating laser. By investigating variations of the beam width parameter in presence of different density profiles it is found that the beam width parameter is considerably decreased for the introduced density ramp comparing with uniform density and earlier introduced density ramp profiles. By using this new density profile high intensity laser pulses are guided over several Rayleigh lengths with extremely small beam width parameter.

scholarly journals Self-compression of two co-propagating laser pulse having relativistic nonlinearity in plasma

2017 ◽  
Vol 35 (4) ◽  
pp. 722-729
Author(s):  
S. Kumar ◽  
P. K. Gupta ◽  
R. K. Singh ◽  
R. Uma ◽  
R. P. Sharma
Keyword(s):  
Laser Beam ◽  
Pulse Width ◽  
Pulse Compression ◽  
Group Velocity Dispersion ◽  
Refractive Index Profile ◽  
Intense Laser ◽  
Laser Beams ◽  
Critical Parameters ◽  
Beam Power ◽  
Laser Beam Intensity

AbstractThe study proposes a semi-analytical model for the pulse compression of two co-propagating intense laser beams having Gaussian intensity profile in the temporal domain. The high power laser beams create the relativistic nonlinearity during propagation in plasma, which leads to the modification of the refractive index profile. The co-propagating laser beams get self- compressed by virtue of group velocity dispersion and induced nonlinearity. The induced nonlinearity in the plasma broadens the frequency spectrum of the pulse via self-phase modulation, turn to shorter the pulse duration and enhancement of laser beam intensity. The nonlinear Schrodinger equations were set up for co-propagating laser beams in plasmas and have been solved in Matlab by considering paraxial approximation. The propagation characteristics of both laser beams inside plasma are divided into three regions through the critical divider curve, which has been plotted between pulse width τ01 and laser beam power P01. Based on the preferred value of critical parameters, these regions are oscillatory compression, oscillatory broadening, and steady broadening. In findings, it is observed that the compression of the laser beam depends on the combined intensity of both beams, plasma density, and initial pulse width.

scholarly journals Electron and photon beams interacting with plasma

2006 ◽  
Vol 364 (1840) ◽  
pp. 635-645 ◽  
Author(s):  
Albert Reitsma ◽  
Dino Jaroszynski
Keyword(s):  
Laser Pulse ◽  
Electron Bunch ◽  
Laser Pulses ◽  
Plasma Waves ◽  
Intense Laser ◽  
Wave Number ◽  
Collective Effects ◽  
Photon Beams ◽  
Wave Dynamics ◽  
Intense Laser Pulses

A comparison is made between the interaction of electron bunches and intense laser pulses with plasma. The laser pulse is modelled with photon kinetic theory , i.e. a representation of the electromagnetic field in terms of classical quasi-particles with space and wave number coordinates, which enables a direct comparison with the phase space evolution of the electron bunch. Analytical results are presented of the plasma waves excited by a propagating electron bunch or laser pulse, the motion of electrons or photons in these plasma waves and collective effects, which result from the self-consistent coupling of the particle and plasma wave dynamics.

Effect of obliquely external magnetic field on the intense laser pulse propagating in plasma medium

2020 ◽  
Vol 34 (07) ◽  
pp. 2050044
Author(s):  
Mehdi Abedi-Varaki
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Laser Pulse ◽  
Magnetoactive Plasma ◽  
Spot Size ◽  
The Self ◽  
Intense Laser ◽  
Intense Laser Pulse ◽  
Laser Spot Size ◽  
Self Focusing

In this paper, self-focusing of intense laser pulse propagating along the obliquely external magnetic field on the collisional magnetoactive plasma by using the perturbation theory have been studied. The wave equation describing the interaction of intense laser pulse with collisional magnetoactive plasma is derived. In addition, employing source-dependent expansion (SDE) method, the analysis of the laser spot-size is discussed. It is shown that with increasing of the angle in obliquely external magnetic field, the spot-size of laser pulse decreases and as a result laser pulse becomes more focused. Furthermore, it is concluded that the self-focusing quality of the laser pulse has been enhanced due to the presence of obliquely external magnetic field in the collisional magnetoactive plasma. Besides, it is seen that with increasing of [Formula: see text], the laser spot-size reduces and subsequently the self-focusing of the laser pulse in plasma enhances. Moreover, it is found that changing the collision effect in the magnetoactive plasma leads to increases of self-focusing properties.

scholarly journals Combined effect of relativistic and ponderomotive nonlinearity on self-focusing of Gaussian laser beam in a cold quantum plasma

2016 ◽  
Vol 34 (3) ◽  
pp. 426-432 ◽  
Author(s):  
H. Kumar ◽  
M. Aggarwal ◽  
Richa ◽  
T.S. Gill
Keyword(s):  
Laser Beam ◽  
Beam Width ◽  
Combined Effect ◽  
Quantum Plasma ◽  
Gaussian Laser Beam ◽  
Relativistic Case ◽  
Self Focusing ◽  
Ponderomotive Nonlinearity ◽  
Paraxial Ray ◽  
The Impact

AbstractIn the present paper, we have investigated self-focusing of Gaussian laser beam in relativistic ponderomotive (RP) cold quantum plasma. When de Broglie wavelength of charged particles is greater than or equal to the inter particle distance or equivalently the temperature is less than or equal to the Fermi temperature, quantum nature of the plasma constituents cannot be ignored. In this context, we have reported self-focusing on account of nonlinear dielectric contribution of RP plasma by taking into consideration the impact of quantum effects. We have setup the nonlinear differential equation for the beam-width parameter by paraxial ray and Wentzel Kramers Brillouin approximation and solved it numerically by the Runge Kutta Fourth order method. Our results show that additional self-focusing is achieved in case of RP cold quantum plasma than relativistic cold quantum plasma and classical relativistic case. The pinching effect offered by quantum plasma and the combined effect of relativistic and ponderomotive nonlinearity greatly enhances laser propagation up to 20 Rayleigh lengths.

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