The Juno probe, which studies the Jupiter system, continues to increase our knowledge of the Jovian magnetosphere and environment. Thanks to onboard instruments such as JEDI and JADE, measurements of the energy spectra of charged particles precipitating in the auroral regions enabled us to establish the most realistic energy distributions for these precipitating electrons. These distributions can be fitted by a phenomenological function (as the example of Coumans et al. 2002) defined by a characteristic energy E0 and a kappa parameter describing its broadness over high energies.

Considering the distance between the probe's measurement altitude and the impact position of charged particles, particularly electrons, where auroral emissions are produced, these energetic distributions of magnetospheric particles are influenced by various phenomena such as Alfvén wave-particle interaction. These processes can accelerate or decelerate these particles, altering their average energy. Therefore, particle energy distributions measured at the Juno probe may differ from those observed at auroral altitudes.

In this study, we developed a UV emission model, which we combined with an electron transport model to simulate the auroral spectral emission of H2 molecules in the UV range. Based on observations of the Jovian aurora by the UVS instrument on board Juno, we derived the characteristic energies of the electrons precipitating in the auroral regions during PJ32. For this, we modeled the relationship between the color ratio (CR) and the average energy of precipitated electrons. In a first step, we consider monoenergetic electron flux. In a second step, we consider fluxes following a kappa energy distribution with kappa = 2.5.

Finally, we were able to establish characteristic energy maps for electrons precipitated in Jupiter's auroral regions. In comparison with previous similar studies, and based on HST observations, we found that modeling the CR with a monoenergetic distribution led to an underestimation of the average energy of electrons precipitating in the auroral regions by a factor of 3 to 5.

In conclusion, we have established a more realistic estimation of electron energy flux distributions at auroral altitudes. We now have the possibility of deriving maps of the mean energy of precipitating electrons from UVS observations for other Juno perijoves.