Transient feedback and global instability in non-homogeneous systems

Abstract

Model examples of linear wave systems are considered to illustrate the origin of feedback instability in situations involving strong transients. Two mechanisms of transient growth are addressed. The first is a spatial amplification of resonant waves propagating in the same direction. The second form of transient growth is purely temporal. It is found that under certain conditions, both forms of transients can trigger global instability in a non-homogeneous system.