Charge state of fast heavy ions in a hydrogen plasma

We report the first charge-state measurements of fast heavy ions passing through a plasma target. The projectiles were ⁴⁰Ar ions at an energy of 4.8 MeV/amu and ¹²⁹Xe ions at an energy of 5.9 MeV/amu. The target was a 20-cm-long Z pinch discharge which provided fully ionized hydrogen plasma with free electron densities up to 1.5×{}10¹⁹ cm^-3. The measured charge-state distributions are in excellent agreement with theoretical calculations. For Xe ions an increase of the ion charge state in plasma over the charge state in cold gas was observed.