Pseudo angular momentum and topological charge conservation for non linear acoustical vortices

Jean-Louis Thomas (1) , Régis Marchiano (1)

1 LMDH - Laboratoire des Milieux Désordonnés et Hétérogènes

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.

Jean-Louis Thomas, Régis Marchiano. Pseudo angular momentum and topological charge conservation for non linear acoustical vortices. Physical Review Letters, 2003, 91 (24), pp.244302. ⟨10.1103/PhysRevLett.91.244302⟩. ⟨hal-00018004⟩