Formation of Hexagonal Patterns: 
Secondary Instabilities and Disorder

Abstract

We consider systems undergoing a bifurcation to hexagonal patterns as is, for instance, the case in a liquid layer heated from below. In particular, we focus on systems with broken chiral symmetry (e.g. by rotation around a vertical axis). Using asymptotic and computational approaches we identify secondary sideband and amplitude instabilities, which lead to periodic and to disordered/chaotic states.