Study of multiple ring ELVES with the Mini-EUSO telescope on-board the International Space Station

Abstract: Mini-EUSO (Multiwavelength Imaging New Instrument for the Extreme Universe Space Observatory) is a telescope observing the Earth in the ultraviolet band (290-430 nm) from the Russian Zvezda module of the International Space Station since 2019. The telescope is capable of observing UV emissions of cosmic, atmospheric, and terrestrial origin on different time scales. Among the atmospheric phenomena that can be studied, ELVES (Emission of Light and Very low-frequency perturbations due to Electromagnetic pulse Sources) have been photographed by Mini-EUSO with a time resolution of 2.5 us. ELVES are rapidly expanding rings of optical and ultraviolet emissions, 75-95 km in height, resulting from the de-excitation of molecular nitrogen and oxygen in the lower ionosphere following a lightning-associated ElectroMagnetic wave Pulse (EMP). A detailed study of their characteristics, such as radius, speed, and energy, is required for the understanding of these phenomena. In this work, results from the observation of about 30 ELVES with Mini-EUSO will be presented. Using dedicated algorithms, their electro-optical dynamics and morphological characteristics have been thoroughly investigated.