Integrating sheath and radiation-based acceleration using scaling coefficients for tailoring radiation dominant hybrid acceleration.

An optimal target condition for generating GeV-energy ions with linearly polarized laser pulse is revealed by a hybrid acceleration theory based on the fractional contributions of the target normal sheath acceleration (TNSA) and the radiation pressure acceleration (RPA) mechanisms in the RPA-dominant regime. The theory is established with two scaling coefficients, which scale the TNSA and RPA velocities, and are sophisticated through two-dimensional particle-in-cell simulations where GeV-energy ions are obtained by RPA-dominant hybrid acceleration. By imposing limits on the scaling coefficients, three separate acceleration regions are obtained including a RPA-dominant acceleration region, which is optimal to generate GeV-energy ions. The past experiment/simulation results are in good agreement with the acceleration regions obtained. This RPA-dominant region is narrower than previously reported, and this region becomes even narrower with increasing material density.