The Generation of Tripoles from Unstable Axisymmetric Isolated Vortex Structures

Abstract

Tripolar coherent vortices are shown to emerge from the unstable evolution of perturbed two-dimensional axisymmetric flows. They are obtained from the nonlinear equilibration of barotropically linearly unstable normal modes, as well as from more general initial perturbations. This instability is proposed as an important mechanism for the generation of both dipolar and tripolar coherent vortex structures.