Features of femtosecond laser pulse reflection from a sharp boundary of relativistic laser plasma

The features of femtosecond laser pulse reflection from a plasma target of near-critical density were analytically and numerically studied in a wide range of laser pulse intensities and durations. Based on analytical calculations, it is shown that the pulse reflectance at a constant intensity decreases with decreasing pulse duration. Based of numerical simulation results, it is shown that, as a superintense femtosecond laser pulse is incident on a plasma layer with a concentration close to the critical one, a quasi-periodic electron-density structure is formed in the plasma bulk, which can both increase and decrease the the laser pulse reflectance.