Surface instabilities in granular matter and ion-sputtered surfaces
  We apply a theoretical approach, originally introduced to describe aeolian ripples formation in sandy deserts, to the study of surface instability in ion sputtered surfaces. The two phenomena are distinct by several orders of magnitudes and by several physical mechanisms, but they obey to similar geometrical constraints and therefore they can be described by means of the same approach. This opens a novel conceptual framework for the study of the dynamical surface roughening and ripple formation on crystal and amorphous surfaces during ion sputtering. 
T. Aste and U. Valbusa