LASER INTERACTION WITH A SHARP-EDGED OVERDENSE PLASMA

Recent studies on short-pulse interaction with steep-density gradient plasmas (L/lambda-0) uncovered some new absorption mechanisms. One such process was proposed by Brunel (1987), in which a laser beam is obliquely incident on a perfectly conducting surface. During one half-cycle, electrons dragged from the surface into the vacuum region are returned to the plasma with velocities of the same order as that of the quiver electron velocity. We have reexamined this mechanism using a 1-D (Lagrangian) plasma model, but without Brunel's assumption that the electric field vanishes inside the plasma. Analytical and numerical calculations of electron trajectories and the self-consistent electric fields are presented and comparisons are made with 1-D particle-in-cell simulations.