We address the striking coexistence of localized waves ("pulses") of different lengths, which was observed in recent experiments and full numerical simulations of binary-mixture convection. Using a set of extended Ginzburg-Landau equations, we show that this multiplicity finds a natural explanation in terms of the competition of two distinct, physical localization mechanisms; one arises from dispersion and the other from a concentration mode. This competition is absent in the standard Ginzburg-Landau equation. It may also be relevant in other waves coupled to a large-scale field.

• Received 15 May 1995

DOI:https://doi.org/10.1103/PhysRevLett.75.4035