Bubble-like structures generated by activation of internal shape modes   in two-dimensional sine-Gordon line solitons
  Nonlinear waves that collide with localized defects exhibit complex behavior. Apart from reflection, transmission, and annihilation of an incident wave, a local inhomogeneity can activate internal modes of solitons, producing many impressive phenomena. In this work, we investigate a two-dimensional sine-Gordon model perturbed by a family of localized forces. We observed the formation of bubble-like and drop-like structures due to local internal shape modes instabilities. We describe the formation of such structures on the basis of a one-dimensional theory of activation of internal modes of sG solitons. An interpretation of the observed phenomena, in the context of phase transitions theory, is given. Implications in Josephson junctions with a current dipole device are discussed. 
M\'onica A. Garc\'ia-\~Nustes, Jorge A. Gonz\'alez, and Juan F.   Mar\'in
nlin.PS