Quasi-geostrophic vortex vertical alignment in near collapse interactions

Abstract

We consider a three-vortex interaction which leads to the vertical alignment of two like-signed quasi- geostrophic vortices in a continuously stratified, rotating fluid. The interaction is close to the classical collapse interaction of three co-planar vortices except that the vortices centres move on close but differ- ent horizontal planes. The vertical alignment of vortices helps create larger structures and contributes in physical space to the inverse energy cascade observed in spectral space in geostrophic turbulence.