  The visco-diffusive McIntyre instability (McIntyre 1970) has been suggested
as a possible source for density layer formation around laboratory and oceanic
vortices. This suggestion is here quantitatively addressed using idealised,
axisymmetric, numerical simulations of a simple Gaussian-like vortex in thermal
wind balance, floating in a rotating, stratified flow. Numerical simulations
are complemented by a local stability analysis derived from the seminal study
(McIntyre 1970). It is confirmed that the McIntyre instability is responsible
for the layering observed around laboratory vortices, but its relevance for
explaining layering around meddies remains doubtful.
