Evolution of a Gaussian laser beam in warm collisional magnetoplasma

Abstract

In this paper, the spatial evolution of an intense circularly polarized Gaussian laser beam propagated through a warm plasma is investigated, taking into account the ponderomotive force, Ohmic heating, external magnetic field, and collisional effects. Using the momentum transfer and energy equations, both modified electron temperature and electron density in plasma are obtained. By introducing the complex dielectric permittivity of warm magnetized plasma and using the complex eikonal function, coupled differential equations for beam width parameter are established and solved numerically. The effects of polarization state of laser and magnetic field on the laser spot size evolution are studied. It is observed that in case of the right-handed polarization, an increase in the value of external magnetic field causes an increase in the strength of the self-focusing, especially in the higher values, and consequently, the self-focusing occurs in shorter distance of propagation. Moreover, the results demonstrate the existence of laser intensity and electron temperature ranges where self-focusing can occur, while the beam diverges outside of these regions; meanwhile, in these intervals, there exists a turning point for each of intensity and temperature in which the self-focusing process has its strongest strength. Finally, it is found that the self-focusing effect can be enhanced by increasing the plasma frequency (plasma density).

Effects of the evolution of two cross‐focused Gaussian laser beams on the terahertz generation in thermal collisional plasma

“…[31] , the modified electron density distribution because of this ponderomotive force can be represented as follows Typically, Λ is a large number and ln Λ = 10-20 for the various types of plasmas.…”

“…31 and used the dimensionless variables j = To achieve the equations of Gaussian laser beam evolution in the plasma, we adopted a similar method to that reported in ref.…”

Enhancement of electron density in the interaction of high‐power electromagnetic waves with inhomogeneous magnetized plasma

“…Hence, the ion temperature is neglected. The ponderomotive force in Equations (7) and (9) in the presence of external magnetic field is [ 24,25 ] where m e is the electron mass, and ν ei is the electron–ion collision frequency. ω c = | q | B / m e c is the electron cyclotron frequency, and B is the external static magnetic field.…”

“…Hence, the ion temperature is neglected. The ponderomotive force in Equations (7) and (9) in the presence of external magnetic field is [24,25] ⃗ F p = − n e e 2 4m e ( 2 + 2 ei − c 2 )…”

Influence of Magnetic field and Decentred Parameter on Self-Focusing of CoshGaussian Laser Beam in Collisional Magnetized Plasma

“…The nonlinear interaction of high-intensity laser pulse with plasmas is attractive due to its relevance to laser wake-field acceleration, X-ray lasers, acceleration of charged particles, laser-driven fusion, optical harmonic generation, and fast igniters concept of inertial confinement fusion [1][2][3][4][5][6][7][8][9][10]. All these applications need the laser beams to propagate over several Rayleigh lengths in the plasmas without loss of energy as well as it is necessary to know the propagation characteristics of the laser beam while getting an efficient interaction with plasma [11][12]. In a nonlinear medium like dielectrics, semiconductors, and plasmas, the phenomenon of self-focusing being a genuinely nonlinear optical process is induced by the modification of a material's refractive index to an intense laser beam [13].…”