Understanding the Origin of Jupiter's Diffuse Aurora Using Juno's First Perijove Observations. Issue 20 (28th October 2017)

• Record Type: Journal Article
• Authors: Li, W.; Thorne, R. M.; Ma, Q.; Zhang, X.‐J.; Gladstone, G. R.; Hue, V.; Valek, P. W.; Allegrini, F.; Mauk, B. H.; Clark, G.; Kurth, W. S.; Hospodarsky, G. B.; Connerney, J. E. P.; Bolton, S. J.
• Is Part Of: Geophysical research letters. Volume 44:Issue 20(2017)
• Page Start: 10, 162
• Page End: 10, 170
• Publication Date: 2017-10-28
• Subjects: Jupiter -- diffuse aurora -- Juno -- pitch angle scattering -- whistler mode waves; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL075545
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Juno observed the low‐altitude polar region during perijove 1 on 27 August 2016 for the first time. Auroral intensity and false‐color maps from the Ultraviolet Spectrograph (UVS) instrument show extensive diffuse aurora observed equatorward of the main auroral oval. Juno passed over the diffuse auroral region near the System III longitude of 120°–150° (90°–120°) in the northern (southern) hemisphere. In the region where these diffuse auroral emissions were observed, the Jupiter Energetic Particle Detector Instrument (JEDI) and Jovian Auroral Distributions Experiment (JADE) instruments measured nearly full loss cone distributions for the downward going electrons over energies of 0.1–700 keV but very few upward going electrons. The false‐color maps from UVS indicate more energetic electron precipitation at lower latitudes than less energetic electron precipitation, consistent with observations of precipitating electrons measured by JEDI and JADE. The comparison between particle and aurora measurements provides first direct evidence that these precipitating energetic electrons are mainly responsible for the diffuse auroral emissions at Jupiter. Key Points: Diffuse auroral emissions were observed in a broad region located equatorward of the main oval by Juno In the diffuse auroral region, precipitating electrons with nearly full loss cone distributions were observed over 100 s eV‐100 s keV The pattern of characteristic energy of precipitating electrons is consistent with the auroral Juno‐UVS false‐color map