Generation of energetic ring-shaped ion beam from relativistic Laguerre-Gaussian laser pulse interacting with micro-structure targets

By using three-dimensional particle-in-cell simulations, we demonstrate that an energetic ring-shaped ion beam can be generated by an ultra-intense circularly polarized Laguerre-Gaussian laser pulse interacting with micro-structure targets. The electron and ion dynamics of three different targets including a sleeve-wire target, wire target, and common planar target are investigated. It is found that an optimized sleeve-wire target can provide a remarkable increase in the maximum ion energy and laser-to-ion energy conversion efficiency. The reason can be attributed to the matched transverse profiles between the electric-field distribution of Laguerre-Gaussian laser and sleeve-wire structure, resulting in efficient laser-target energy coupling. In fact, using a laser pulse of intensity 2.74 x 10(20) W/cm(2), duration 66.7 fs, and energy similar to 1J, one can obtain similar to 35MeV protons, similar to 5.8MeV/u carbon ions, and similar to 15% laser-to-ion energy conversion. Published under license by AIP Publishing.