IONIZATION AND STOPPING OF HEAVY-IONS IN DENSE LASER-ABLATED PLASMAS

Enhanced plasma stopping and enhanced projectile ionization in plasma are considered within the framework of the standard stopping model (SS M), the most economical extension to plasmas of the standard cold-matt er formalism. The main goal of this work is to check quantitatively th e SSM predictions using the setup SPQR1 (stopping plasma quantitativel y reinforced) developed at Bruyeres-le-Chatel. It consists of a laser- ablated C or Al plasma synchronized with a 50-MeV Cu ion beam bunched out of a tandem Van de Graaff accelerator. A combination of a Thomson parabola spectrometer and an ionographic tube provides charge-state di stribution and energy-loss data. Plasma expansion is modeled and yield s electron-temperature and density-profile-matching diagnostics perfor med in the interaction chamber. In agreement with theoretical expectat ions, charge-distribution maxima at the plasma exit are shifted toward higher ionization compared to the equivalent results in cold matter. The distribution width is smaller than its cold-target homologue. Ener gy losses in partially ionized C and Al targets are several times larg er than in the respective cold solid. The relevance to heavy-ion-drive n inertial fusion is emphasized.