Intense laser pulse driven ion acceleration in expanding foil plasmas

Summary form only given, as follows. In the present work, we investigate numerically various mechanisms of energetic ion emission from slab targets irradiated by a picosecond pulse laser, as well as very intense subpicosecond pulse lasers and effect of contamination on these mechanisms. We use the particle-in-cell simulation employing the average ion model to include transient plasma ionization and Langevin equation to calculate elastic collisions. Results of recent experiments with foil plasmas irradiated by the 12 TW, 60 fs laser facility of NERL are discussed. The new mechanism of ion acceleration in a solitary wave is proved to be the most efficient providing ion energy E -(3-10) MeV/nucleon at laser intensity I/spl sim/10/sup 19/ W/cm/sup 2/ and useful as a high-current ion source for conventional accelerators for radiology.