Suppressing longitudinal double-layer oscillations by using elliptically   polarized laser pulses in the hole-boring radiation pressure acceleration   regime
  It is shown that well collimated mono-energetic ion beams with a large particle number can be generated in the hole-boring radiation pressure acceleration regime by using an elliptically polarized laser pulse with appropriate theoretically determined laser polarization ratio. Due to the $\bm{J}\times\bm{B}$ effect, the double-layer charge separation region is imbued with hot electrons that prevent ion pileup, thus suppressing the double-layer oscillations. The proposed mechanism is well confirmed by Particle-in-Cell simulations, and after suppressing the longitudinal double-layer oscillations, the ion beams driven by the elliptically polarized lasers own much better energy spectrum than those by circularly polarized lasers. 
Dong Wu, C. Y. Zheng, C. T. Zhou, X. Q. Yan, M. Y. Yu and X. T. He
physics.plasm-ph