AOPP Seminar - The dynamics of Jupiter’s polar vortex crystals

Abstract - In the atmospheres of most solar-system planets, polar vortices are isolated single cyclones centred over or near the poles. By contrast, Jupiter’s polar vortices have an unprecedented structure, as discovered by NASA’s Juno probe, having a single cyclone over each pole surrounded by several other cyclones in crystalline patterns. Later observations show that the number of cyclones in these crystals can vary with time. These crystalline structures, and their temporal dependence, were not predicted prior to being observed, and the mechanisms explaining their formation and evolution remain poorly understood. Much of the existing work looking at these vortex crystals has focussed on how the crystals remain stable. This stability seems to be (at least partly) a result of the cyclones being so-called ‘shielded vortices’, whereby the cyclones have a small region of anticyclonic vorticity that surrounds them. However, comparatively little work has looked at aspects of the crystals’ behaviour beyond their stability. In this talk I will give an overview of our research group’s work looking at these crystals, largely using simplified dynamical models. I will particularly focus on the processes that set the speed with which the circumpolar cyclones move around the central cyclone, and how the crystals respond to ‘intruder’ cyclones. I will also give future directions for our work on understanding Jupiter’s polar regions.