Low- and medium-mass ion acceleration driven by petawatt laser plasma interactions

An experimental investigation of low- and medium-mass ion acceleration from resistively heated thin foil targets, irradiated by picosecond laser pulses at intensities up to 5 × 1020 W cm−2, is reported. It is found that the spectral distributions of ions, up to multi-MeV/nucleon energies, accelerated from the rear surface of the target are broadly consistent with previously reported measurements made at intensities up to 5 × 1019 W cm−2. Properties of the backward-directed beams of ions accelerated from the target front surface are also measured, and it is found that, compared with the rear surface, higher ion numbers and charges, and similar ion energies are produced. Additionally, the scaling of the maximum ion energy as a function of ion charge and laser intensity are measured and compared with the predictions of a numerical model.