This article reports on the interaction between slow
ions and a partially ionized plasma. Temporal evolutions
of energy loss and charge distribution of 2.4 MeV oxygen
beams in the laser-induced polyethylene plasma were measured.
The charge distribution showed strong stripping ability
in the early phase of the plasma. Stopping power deduced
from the experimental energy loss was 1.9 times larger
than that for the solid. The effective charge of the projectile
ion was estimated from the yields of 4+ and 6+ states.
The peak value of the effective charge was 1.4 times larger
than that of the solid. The stopping power equation given
by Sigmund was extended for the partially ionized plasma
and it could reproduce the measured energy loss.
Energy Loss of Excited Slow Ions in Electron Gas
