Self-focusing Of Intense Laser Beam Research Articles

Self-focusing of a laser beam in the rippled density magnetoplasma

In the present paper, we have investigated the self-focusing of intense laser beam in rippled density magnetoplasma. The differential equation for the beam width parameter is obtained by following WKB and paraxial approximations and solved it numerically. The behaviour of beam width parameter with dimensionless distance of propagation is extensively investigated for different values of laser and plasma parameters and is strongly influenced by the magnetic field. The results are discussed and presented graphically. It is seen that the density ripple of suitable wave number increases the self-focusing property of laser beam in magnetoplasma. Meanwhile, an increase in the values of magnetic field increases the strength of the self-focusing, especially in shorter distance of propagation. Furthermore, increase in plasma frequency (plasma density) causes more reduction in the spot size of laser beam and consequently increases the rate of self-focusing of laser beam in magnetoplasma.

Relativistic self-focusing of intense laser beam in thermal collisionless quantum plasma with ramped density profile

Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum plasma and classical plasma. It is realized that the laser self-focusing in the quantum plasma becomes stronger in comparison with the classical regime.

Relativistic Self-Focusing of Intense Laser Beam in Magnetized Plasma

Relativistic Self-Focusing of Intense Laser Beam in Magnetized Plasma

Stationary self-focusing of intense laser beam in cold quantum plasma using ramp density profile

By using a transient density profile, we have demonstrated stationary self-focusing of an electromagnetic Gaussian beam in cold quantum plasma. The paper is devoted to the prospects of using upward increasing ramp density profile of an inhomogeneous nonlinear medium with quantum effects in self-focusing mechanism of high intense laser beam. We have found that the upward ramp density profile in addition to quantum effects causes much higher oscillation and better focusing of laser beam in cold quantum plasma in comparison to that in the classical relativistic case. Our computational results reveal the importance and influence of formation of electron density profiles in enhancing laser self-focusing.

Numerical investigation of relativistic self-focusing of intense laser beam with LG01 mode in plasmas

In this paper, we numerically investigate the relativistic self-focusing of laser beam with LG01 mode in plasmas. An effective potential is introduced to identify the critical power. Numerical methods are employed to solve the governing equations. To verify the numerical procedures, we compare the known analytical solution of the relativistic critical power for TEM00 mode with our numerical method. It is shown that there is a good agreement between our numerical results and the analytical solution. The critical power for relativistic self-focusing of a LG01 laser beam is about 6 times of that for a TEM00 laser beam.

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

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.

Non-stationary self-focusing of intense laser beam in plasma using ramp density profile

The non-stationary self-focusing of high intense laser beam in under-dense plasma with upward increasing density ramp is investigated. The obtained results show that slowly increasing plasma density ramp is very important in enhancing laser self-focusing. Also, the spot size oscillations of laser beam in front and rear of the pulse for two different density profiles are shown. We have selected density profiles that already were used by Sadighi-Bonabi et al. [Phys. Plasmas 16, 083105 (2009)]. Ramp density profile causes the laser beam to become more focused and penetrations deeps into the plasma by reduction of diffraction effects. Our computations show more reliable results in comparison to the previous works.

Improving the relativistic self-focusing of intense laser beam in plasma using density transition

The propagation of a Gaussian beam in underdense plasma with upward increasing density ramp is analyzed. In this work are shown that the spot size oscillations of laser beam increases and its amplitude shrinks with proper plasma density ramp. This causes the laser beam to become more focused and penetrations deep into the plasma by reduction of diffraction effect. The related focusing parameters are optimized to get the best possible focusing at the relativistic threshold intensity of Nd-glass laser and the effect of the laser intensity in the self-focusing parameters is also investigated. The analytical calculations are presented and showed more reliable results in comparison to the previous works.

Self-focusing of intense laser beam in magnetized plasma

In this paper, evolution of spot size of an intense laser beam in cold, underdense, magnetized plasma has been studied. The plasma is embedded in a uniform magnetic field perpendicular to both, the direction of propagation and electric vector of the radiation field. Nonlinear current density is set up and the source dependent expansion method is used to determine the evolution of the spot size of a laser beam having a Gaussian profile. It is shown that transverse magnetization of plasma enhances the self-focusing property of the laser beam leading to reduction in critical power required to self-focus the beam.