Multiple species laser-driven ion-shock acceleration*

The particle-in-cell code OSIRIS was used to study the effects of multiple ion species on laser-driven collisionless shock acceleration. Two-dimensional plasma slab simulations composed of protons, carbon, and electrons were used to study the effects of plasma composition, ion change state, and the ratio of downstream to upstream plasma density on the generation of collisionless shocks. Two shocks were formed at large density ratios with the faster primary shock reflecting protons and the slower secondary shock reflecting carbon ions. The velocities of these shocks cannot be accurately predicted by current collisionless shock theory because a kinetic model is required to describe the interaction of the ion populations. Laser-driven shock simulations were performed where the ion composition was varied. However double shocks were only formed when steep density profiles were used. The implications for laser-driven ion shock experiments will be discussed.