title: Pseudo angular momentum and topological charge conservation for nonlinear acoustical vortices.
abstract: We study acoustical vortices (AVs) and their connection with optical vortices (OVs). We show that AVs and OVs have the same properties if the concept of pseudomomentum is used. Radiation stress and conservation of topological charge are obtained with the pseudomomentum rule. In a weak nonlinear regime, the conservation of pseudo angular momentum imposes a linear increase of the topological charge with the harmonic order. This last result is experimentally verified.
authors.affiliation: LMDH, Université Paris 06, UMR C.N.R.S. 7603, 4 place Jussieu, 75252 Paris CEDEX 05, France. thomasjl@ccr.jussieu.fr
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Thomas
authors.forename: Régis
authors.initials: R
authors.lastname: Marchiano