Development and simulated observations of the Jovian Neutrals Analyzer

Abstract: This thesis deals with the development of the Jovian Neutrals Analyzer (JNA) for the Jupiter ICy moons Explorer (JUICE) mission to Jupiter, planned to launch in 2023. Jupiter, the largest planet in the Solar System, orbits the Sun at five times the distance from the Earth to the Sun, accompanied by dozens of moons, rings, and the largest object in the SolarSystem: the Jovian magnetosphere. Born of the interaction betweenthe solar wind and Jupiter’s strong magnetic field, the Jovian magneto-sphere is host to a number of unique, complex phenomena, includingthe creation of a sheet of energetic particles orbiting the giant planetand interacting with its four largest moons: Io, Europa, Ganymede, and Callisto.A better understanding of Jupiter’s magnetosphere and its interaction with its four largest moons is one of the main objectives of the JUICE mission. To achieve this goal, JUICE is equipped with the Particle Environment Package (PEP), comprised of six particle sensors, including JNA. By measuring low-energy Energetic Neutral Atoms (ENAs) in the range from 10 eV to 3.3 keV, JNA will image the plasma co-located with the orbit of Io, and reveal ion precipitation patterns at the surface of Jupiter’s icy moons.JNA improves on its predecessors (CENA on Chandrayaan-1 and ENA on BepiColombo) by featuring a higher angular resolution, with a 150◦ field-of-view divided into 11 pixels. JNA is also more resistant to radiation, a necessary improvement to be able to make measurements in the harsh radiation environment expected in the Jovian system. To measure ENAs in the low-energy range, JNA uses a charged particle deflector to remove ambient ions; a charge conversion surface to ionize incoming neutral particles, which are then energy-analyzed by an electrostatic wave system; and a Time-of-Flight cell to derive the mass of the original particle.In this work, we report on how JNA was designed, developed, and calibrated. We show the first results of JNA’s calibration campaign, and compare them to its expected performance. Finally, to facilitate the interpretation of JNA data at Jupiter, we estimate ENA fluxes expected at Ganymede and use our results to simulate JNA observations.