Dynamics and bifurcation of passive tracers advected by a ring of point vortices on a sphere

We consider the dynamics of a passive tracer, advected by the presence of a latitudinal ring of identical point vortices. The corresponding instantaneous motion is modeled by a one degree of freedom Hamiltonian system. Such a dynamics presents a rich variety of behaviors with respect to the number o...

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Bibliographic Details
Authors: Andrade, J., Boatto, S., Vidal, C.
Format: article
Status:Published version
Publication Date:2019
Country:España
Institution:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repository:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2072/530701
Online Access:http://hdl.handle.net/2072/530701
Access Level:Open access
Keyword:Matemàtiques
Física
51
Description
Summary:We consider the dynamics of a passive tracer, advected by the presence of a latitudinal ring of identical point vortices. The corresponding instantaneous motion is modeled by a one degree of freedom Hamiltonian system. Such a dynamics presents a rich variety of behaviors with respect to the number of vortices, N, and the ring’s co-latitude, θo—or, equivalently, its vertical position qo = cos θo. We carry out a complete description of the global phase portrait for the cases N = 2, 3, 4 by determining equilibrium points, their stability, and bifurcations with respect to the parameter θo, and by characterizing the separatrix skeleton. Moreover, for N ≥ 5, we prove the existence of a value of bifurcation θoN such that when θo = θoN (θo = π − θoN, respectively) the south (north, respectively) pole becomes a N-bifurcation point, i.e., a symmetric web of N centers and N saddles bifurcates from the corresponding pole.