Instabilities in interaction of circularly polarized laser pulse and overdense target

Abstract

Instabilities in the interaction of a normal intensity circularly polarized pulse and an overdense foil are investigated with two and three dimensional particle-in-cell simulations. Two typical instabilities were shown during the interaction. One is the Weibel-like instability induced by the current far above the Alfven limit, and the other is the boundary instability with ring structures spreading to the center from the boundary which is induced by the transverse boundaries of the target or the laser pulse. These instabilities are important to the proton acceleration by using moderate laser pulses at intensities accessible experimentally with existing laser systems.