Energy loss and charge state measurements of heavy ions passing a hydrogen plasma

Abstract

The accelerator facilities at GSI, consisting of a high current radio frequency quadrupole accelerator (MAXILAC), a rf‐linac (UNILAC), a heavy ion synchrotron (SIS) and an experimental storage ring (ESR) provide unique opportunities to study beam target interaction phenomena over a wide range of beam energy. This range extends from 45 keV/u up to 2 GeV/u. Thus rf‐accelerator and beam‐target interaction physics issues for heavy‐ion‐beam driven inertial confinement fusion can be studied. Recent results of stopping power experiments at UNILAC verified an enhanced energy loss of heavy ions in a plasma of a factor three at beam energies of 1–6 MeV/u. Even bigger differences in stopping power and charge state between ionized and cold matter are expected for beam velocities of the same order of magnitude as the thermal electron velocities in a plasma. A new energy loss experiment in this parameter range has been started at MAXILAC. First results indicate a tremendous enhancement of energy loss in a plasma at beam energies below 45 keV/u.