LAUSR

An analysis of dynamics of a quadruple laser pulse propagating through an under-dense plasma is presented. The Drude model is used to derive the dielectric function of the plasma for relativistic non-linearity in the electron mass. An approximate numerical solution of the nonlinear Schrodinger wave equation for the field of the laser beam is obtained with the help of the moment theory approach in the Wentzel–Kramers–Brillouin (WKB) approximation. Particular emphases are placed on the variations of spot size, pulse width, and longitudinal phase delay with the distance of propagation through the plasma. Self-trapping of the laser pulse is also investigated.