Energetic ions at moderate laser intensities using foam-based multi-layered targets

The experimental feasibility of the laser-driven ion acceleration concept with multi-layered, foam-based targets has been investigated. Targets with the required features have been produced and characterized, exploiting the potential of the pulsed laser deposition technique. In the intensity range 1016-1017 Wcm-2, they allow us to obtain maximum proton energies 2-3 times higher compared to bare solid targets, able to reach and surpass the MeV range with both low and ultrahigh contrast pulses. The results of two-dimensional particle-in-cell simulations, supporting the interpretation of the experimental results, and directions to exploit the concept also at ultrahigh intensities, are presented.