Low Velocity Proton Stopping in Negative Hydrogen-Proton Mixtures

We consider a charge neutral plasma target built on binary ionic mixtures (BIM) with classical electrons. Electron and ion contributions to the proton projectile low velocity ion slowing down (LIVSD) for projectile velocity Vp$<$Vthe (Vthe, target thermal electron velocity)are quantitatively estimated within a dielectric formalism restricted to the quadratic dependence in the projectile charge. The target BIM is constituted of hydrogen negative ions and bare protons in any proportion. Proton LIVSD quantitatively documents a monotoneous decay of free electron density with the increasing relative proportion of negative hydrogen ions,up to equi-proportionality. Possible diagnostics of low-temperature plasmas with T~3000-4000$^{\circ}$K with total ion density ranging around 10$^{11}$ cm$^{-3}$ are also discussed.