Low velocity ion slowing down in a demixing binary ionic mixture

Complete text of publication follows. We consider ion projectile slowing down at low velocity Vp ≤ Vthe, target thermal electron velocity, in a strongly coupled (Gamma-60) and demixing hydrogen-helium ionic mixture of astrophysical concern. It is investigated in terms of quasi-static and critical charge-charge structure factor for each ion species out of the HNC-scheme. Non-polarizable as well as polarizable partially degenerate electron background are given attention. The given low velocity ion slowing down turns negative in the presence of long wavelength and low frequency hydrodynamic modes, signalling a critical demixtion. The superelastic process thus documents an energy transfer from the target ion plasma to incoming ion projectile.