The fluid dynamics of aerosol-filled vortices

A new and unexpected phenomenon has recently been detected following strong wildfire events and volcanic eruptions. Long-lived rising bubbles of wildfire or volcanic aerosol contained within strong anticyclonic vortices have been observed in the stratosphere. Heating through absorption of solar radiation has been hypothesised as driving these structures. Yet the observed single-sign vortices are inconsistent with the dynamical response to localised heating, which predicts a dipole vortex structure. In this talk, we present results that resolve this apparent difference. First, we will present simple axisymmetric models incorporating two-way interaction between dynamics and aerosol combined with insight from vortex dynamics to explain aspects of observed behaviours, including ascent rate and vorticity magnitude, and to suggest criteria for formation. The structure predicted by such axisymmetric models includes an anticyclone that ascends with the tracer, but also a trailing cyclonic structure. We will then present findings from 3D, non-axisymmetric simulations of heating-driven vortices in background shear and strain demonstrating the removal of the trailing structure via vortex stripping and explaining the isolated anticyclones that are observed.