title: Convective and absolute Eckhaus instability leading to modulated waves in a finite box.
abstract: We report an experimental study of the secondary modulational instability of a one-dimensional nonlinear traveling wave in a long bounded channel. Two qualitatively different instability regimes involving fronts of spatiotemporal defects are linked to the convective and absolute nature of the instability. Both transitions appear to be subcritical. The spatiotemporal defects control the global mode structure.
authors.affiliation: Service de Physique de l'Etat Condensé, DSM, CEA Saclay, CNRS SNC 2005, 91191 Gif-sur-Yvette, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Garnier
authors.forename: Arnaud
authors.initials: A
authors.lastname: Chiffaudel
authors.forename: François
authors.initials: F
authors.lastname: Daviaud