Experimental investigation of the Coulomb logarithm in beam–plasma interaction

In order to determine the Coulomb logarithm in the interaction between hot plasma and ion beams, the stopping power of 350 keV protons in a laser plasma target was measured by TOF method. The electron temperature and the electron density of the target plasma was 20 eV and 1018 cm−3, respectively. The Bethe’s Coulomb logarithm calculated using the measured stopping power of protons was 1.8 times as large as that in the beam–cold matter interaction. The mean charge state for 350 keV/u 16O after the interaction with the plasma was also measured by using a time-resolved magnetic spectrograph. The Coulomb logarithm of 350 keV/u 16O was estimated by using measured mean charge state and previously measured stopping power. The obtained Coulomb logarithm for both projectiles are compared.