Multistage ion acceleration in finite overdense target with a relativistic laser pulse

"Multistage ion acceleration" has been analytically and computationally studied in the relativistic regime. For non-relativistic piston velocities, this phenomenon has been described before. But, as we go to relativistic piston velocities, the non-relativistic results hold no more. We have presented a fully relativistic calculation for second stage ion velocities and energies. To verify our calculations, we performed a fully relativistic 1D3V particle in cell simulations using the code LPIC++. It has been found that the relativistic calculations matched very well with the simulation results. Also, it has been seen that at relativistic piston velocities, the non-relativistic results differed by a significant margin. The feasibility of this process has been further established by three dimensional particle in cell simulations