Conditions for the Kelvin-Helmholtz instability in the polar ionosphere

The polar ionosphere is highly structured with density irregularities observed at a wide range of scale sizes: small scale (< 1 km), meso-scale (1–100 km) and large scale (> 100 km). Plasma irregularities are of interest since they may disturb Global Navigation Satellite Systems (GNSS) signals and disrupt High Frequency (HF) communication. Still, the conditions for the formation, the energy cascading from large to small scales and the non-linear evolution of plasma instabilities that cause irregularities in the polar ionosphere are largely unknown. This poster focuses on one of the most commonly invoked instabilities at high latitudes: the Kelvin-Helmholtz instability. The Kelvin-Helmholtz instability can be excited when there exists a shear in the flow velocity. At polar latitudes, flow shears are often observed in relation to auroral arcs, flow channels and reverse flow events. In this work, we use the 3D Geospace Environment Model of Ion-Neutral Interactions (GEMINI) to simulate the Kelvin-Helmholtz instability under various ionospheric conditions. This allows us to characterize the conditions favorable for Kelvin-Helmholtz instability growth. The presented results can be used as a reference to better understand observations of density irregularities under turbulent conditions at high latitudes.