Self-Healing Behavior of Ice

We show that the surface of ice is self-healing: micrometer deep scratches in the ice surface spontaneously disappear by relaxation on a time scale of roughly an hour. Following the dynamics and comparing it to different mass transfer mechanisms, we find that sublimation from and condensation onto the ice surface is the dominant self-healing mechanism. The self-healing kinetics shows a strong temperature dependence, following an Arrhenius behavior with an activation energy of $\Delta E = 58.6 \pm 4.6$ kJ/mole, agreeing with the proposed sublimation mechanism, and at odds with surface diffusion or fluid flow or evaporation-condensation from a quasi-liquid layer.