Nonlocal Ponderomotive Force in a Super Gaussian Laser Beam and the Conditions for Long Time Scale Interaction

Abstract

We have applied the theory of the nonlocal ponderomotive force which we derived recently using the noncanonical Lie perturbation approach to investigate a long time scale particle motion in a super Gaussian laser beam. In such a flat-top beam profile, the local field gradient is diminished near the axis, so that the conventional ponderomotive formula is hardly applied. Numerical analyses of the interaction time and its dependence on the initial position and momentum of particles show that the nonlocal effect of the ponderomotive force, which is associated with higher order spatial derivatives, regulates the dynamics predominantly and sensitively.