Energy loss of fast heavy ions in plasmas

Interaction processes of heavy ions and ionized matter have been investigated experimentally. A Monte Carlo code to simulate charge exchange and energy loss processes in a plasma environment has been developed to plan the experiments, to analyze the results, and to investigate the influence of magnetic fields on the particle trajectories inside the plasma target. The first results of the beam plasma interaction experiments are: The stopping power of ionized matter is increased compared to that of cold, non-ionized matter. This effect is especially pronounced at low ion energies (E < 100 keV/u) where an enhancement factor of up to 40 has been observed. At higher energies (E > 1 MeV/u) this effect is less dramatic, but is still on the order of 2-3, depending on the ion species. The charge state of ions traversing a fully ionized plasma is increased due to reduced capture cross sections of free plasma electrons. It is possible to focus intense heavy ion beams of high magnetic rigidity using a plasma lens. This ideal focusing device achieves a high focusing power for ion beams almost comparable to optical systems for intense beams from high power lasers. Energetic ion beams are very well suited to heat cylindrical target volumes and to create a dense plasma. The characteristic inner-shell target and projectile X-rays provide a tool to analyze the hydrodynamic behavior of beam heated targets with space and time resolution.