Jupiter’s magnetosphere is one of the most fascinating (and largest) bodies in our
Solar System. Many of the physical mechanisms occurring in the Jovian plasma
environment have an impact on the auroral emissions generated in its upper atmosphere, which we study with instruments like the imaging spectrograph onboard the Hubble Space Telescope (HST-STIS). This thesis uses images from STIS to study the equatorward aurorae in the context of other auroral emissions present, and their connection to di!erent magnetospheric phenomena.

The first chapter outlines the key physical mechanisms driving auroral emissions,
describing the Jovian magnetospheric structure and the more relevant dynamics of the plasma, such as the Dungey and Vasyliunas cycles, as well as examining auroras across di!erent bodies in our Solar System for broader context. The second chapter details the instrumentation (HST-STIS imager and Juno’s particle detectors), datasets and processing techniques utilised, including the custom algorithm developed to detect auroral emissions. Chapter three presents a comprehensive statistical study of the auroral emissions in Jupiter’s Southern hemisphere, focusing on the secondary oval and the injection signatures and quantifying its emission frequencies and main characteristics to offer the most complete analysis to date. Chapter four adds an in-situ component, analyzing Juno’s electron data from the JADE particle detector for the equatorward emissions region, and comparing them to the HST observations. The fifth chapter compiles results from three different studies, offering ultraviolet auroral context for Jovian X-ray emissions, its cusp region, and dipolarization front events. In the sixth and final chapter, the main results are synthesised, and some recommendations for expanding on the previous studies are provided.