Polar vortex formation in differentially-rotating 2D disk turbulence

Models of polar vortex formation have seen renewed interest since the Juno mission unexpectedly observed "vortex lattice" states at the poles of Jupiter. These configurations consist of a central polar cyclone surrounded by a ring of multiple circumpolar cyclones—unlike the lone polar cyclones found at the poles of other bodies such as Saturn. Planetary rotation, which induces a vorticity gradient that causes cyclones to migrate towards the pole, is thought to be an essential ingredient for stabilizing these formations. However, studies have yet to confirm whether this proposed stabilizing mechanism is feasible in a forced-dissipative setting for various physical parameters and initial conditions. Here we simulate the emergence of vortices in 2D incompressible turbulence in a disk geometry using the Dedalus framework. We model planetary rotation with the γ-plane approximation and we implement stochastic forcing at small scales. Large scale condensates emerge via an inverse cascade of energy from the forcing scale, and energy is dissipated through both viscosity and large-scale friction. We present findings from simulations with different forcing scales and different strengths of differential rotation. As rotation increases, we transition from the formation of cyclone-anticyclone dipoles to regimes which are unstable for anticyclones but stable for cyclones and zonal flows. We track various length scales induced in the flow by rotation and consider their implications for condensate formation and stability.