Filamentation instability in the interaction of high-order Hermite cosh Gaussian laser beam and inhomogeneous plasmas

Abstract

Based on high order paraxial theory and WKB approximation, filamentation instability in the interaction of high-order Hermite cosh Gaussian laser beam (HchG) and inhomogeneous plasma is studied. By changing the initial light intensity parameters and the non-uniformity of plasma density, the effect of different mode indices beams propagating in uniform and non-uniform plasmas on self-focusing filamentation structures is investigated. The results show that the HchG laser beam exhibits obvious self-focusing and filamentation phenomena along propagation distance in inhomogeneous plasma under the effect of the ponderomotive force. It is found that the mode index of HchG and plasma inhomogeneity have significant effects on filamentation instability, the higher order mode indices of HchG laser beam can strengthen filamentation instability, and plasma inhomogeneity also can enhance filamentation instability. The results provide a useful theoretical basis for effectively regulating the filamentation instability, increasing the peak laser power and designing narrower pulse width lasers.