title: Nonlinear stability of solitons against strong external perturbations.
abstract: We study soliton stability under the action of strong external perturbations. Limits on the weak perturbation approach are established with the help of average Lagrangian methods and full simulations. We found that for the same relative perturbation, larger amplitude solitons develop instability earlier than weaker amplitude solitons.
authors.affiliation: Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: F B
authors.initials: FB
authors.lastname: Rizzato
authors.forename: G I
authors.initials: GI
authors.lastname: de Oliveira
authors.forename: A C-L
authors.initials: AC
authors.lastname: Chian