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We use time-dependent density functional theory coupled with molecular dynamics to study electronic excitations produced by energetic protons ($\mathrm{H^+}$) in solid $\mathrm{Cu}$ over a wide range of proton velocities.   A plane-wave pseudopotential scheme is employed to solve the time-dependent Kohn-Sham equations for a moving ion in the crystal.   These electronic excitations determine the stopping power of the material and alter the interatomic forces for both channeling and off-channeling trajectories.   Our results are in qualitative quantitative  agreement with experiments and models taking into account (for off-channeling trajectories)  the channeling nature of our simulations. Also these results unveil a region of superlinear velocity dependence related to copper crystalline band structure.