North, South, East and West: the asymmetries in the Jovian UV aurorae

Asymmetries in the auroral brightness and morphology carry key information about the origins of these auroral features and allow us to test theoretical models relating magnetospheric processes to their auroral counterpart. In this study, we use Hubble Space Telescope Imaging Spectrograph and Juno-UVS observations of the Jovian UV aurora, separately or in combination, to quantify these asymmetries. For example, focusing on the main emissions, we find that auroral arcs in the dusk side are 3 to 5 times more powerful than in the dawn side (Groulard et al. 2024).
We also show comparisons between aurorae in the northern and southern hemispheres and we show that, on average, their emitted powers in the UV are broadly equivalent. However, when we separate the auroral emissions into three regions, the polar emissions, the main emissions and the outer emissions, we find that polar emissions are brighter in the north, while main emissions are brighter in the south, essentially compensating each other. Zooming in on individual features, we find a good correspondence between features in both hemispheres, except in the polar region, where some features have a clear simultaneous
counterpart while others do not.