Universal Short-Wave Instability of Two-Dimensional Eddies in an Inviscid Fluid

It is shown that a broad class of two-dimensional vortices occurring in the flow of an incompressible, inviscid fluid are unstable to three-dimensional perturbations. At short wavelengths along the vortex axis the growth rate becomes independent of wavelength, and the eigenmode becomes concentrated near the center of the vortex.