Investigation of relativistic self-focusing of Hermite-cosine-Gaussian laser beam in collisionless plasma

Relativistic self-focusing of Hermite-cosine-Gaussian (HcosG) laser beam in plasma has been investigated. The distribution of HcosG laser field in the plasma is closely related to decentered parameter. The differential equation for the beam width parameter is derived by following Wentzel–Kramers–Brillouin (WKB) and paraxial approximation through parabolic wave equation approach. The behavior of beam width parameter with distance of propagation is investigated at different values of plasma density, decentered parameter and intensity parameter. Our results reveal that the laser beam is more focused at lower values of decentered and intensity parameter. Further, a strong oscillatory behavior of the beam width parameter during laser propagation in collisionless plasma is seen.