The impact of whistler mode waves on Jupiter's auroral intensity distribution

Abstract

The diffuse aurora at Jupiter has been studied, and the intensities of its ultraviolet diffuse auroral emissions have been measured. Electrons trapped on closed magnetic field lines are diffused into the atmospheric loss cone through resonant interactions with whistler-mode waves. Observational data collected by the Juno orbiter have been utilized in this study. The precipitation flux of diffused particles into the atmospheric loss-cone has been calculated for five distinct L-shells L = 10, 12, 15, 18, and 20. Additionally, the volume excitation and ionization rates in Jupiter's atmosphere have been determined using the Analytical Yield Spectrum (AYS) approach for electron energy degradation. The calculations have been performed for H Lyman-α from atomic H excitation, H Lyman-α from dissociative excitation of molecular H₂, and the Lyman and Werner bands from H₂ excitation. The height-integrated volume excitation rates yield the intensities of H Lyman-α, Lyman, and Werner bands. At two L-shells, L = 10 and (L = 20), the calculated diffuse auroral intensities for various cases—H Lyman-α, Lyman, and Werner bands—are found to be 97 kR (12 kR), 490 kR (63 kR), and 520 kR (67 kR), respectively. The intensities obtained in this study are approximately 4 to 20 times higher than those estimated in a previous study involving electron cyclotron harmonic (ECH) waves. The electron density in Jupiter's atmosphere has been calculated, with the peak density reaching 2.3 × 10⁷ cm⁻³ at an altitude of 600 km. In contrast, a previous study involving ECH waves found the peak density to be 1 × 10⁷ cm⁻³. Outcomes are discussed.