Nonlinear Steepening of Density Profile by Intense Laser Radiation in Collisional Inhomogeneous Plasmas

The interaction between a high-power electromagnetic wave with an inhomogeneous underdense plasma is studied by considering the ohmic heating caused by laser radiation. Considering the plasma inhomogeneity and ohmic heating, the nonlinear dielectric permittivity is obtained in the collisional regimes. The wave equation is numerically solved and the electromagnetic fields, electron density, electron temperature, and dielectric permittivity profiles are achieved. These profiles show that in the presence of three density profiles, by increasing the laser energy flux, the modified electron density deviates from background electron density and its structure near the critical density becomes highly peaked. Finally, it is found that the amplitude of electron density distribution decreases by increasing the laser wavelength.