Linear dynamics of ion sputtered surfaces: instability, stability and bifurcations.

The linear dynamics of ion sputtered solids is essential to understanding the evolution of ordered and disordered surface patterns. We review the existing models of linear dynamics and point out qualitative discrepancies between theory and experimental observations that characterize the linear regime. In particular, we emphasize the importance of experimental and theoretical analysis of bifurcation points: certain values of control parameters such as ion beam angle or energy, where flat surfaces undergo a transition from stability to instability.