Protons passing through the homogeneous electron gas: Polarization currents, velocities of excited electrons and deposited energy density

The polarization currents and the mean velocities of the electrons that are excited by a moving bare ion in the homogeneous electron gas - represented by the Lindhard dielectric function - are shown for ion velocities below and above the "critical" threshold velocity for plasmon excitations. The deposited power density is derived from the standard formula of the electronic energy loss in the dielectric formulation by a partial integration; it depends exponentially on the distance to the ion track.