Io‐Jupiter decametric arcs observed by Juno/Waves compared to ExPRES simulations. Issue 18 (22nd September 2017)

• Record Type: Journal Article
• Authors: Louis, C. K.; Lamy, L.; Zarka, P.; Cecconi, B.; Imai, M.; Kurth, W. S.; Hospodarsky, G.; Hess, S. L. G.; Bonnin, X.; Bolton, S.; Connerney, J. E. P.; Levin, S. M.
• Is Part Of: Geophysical research letters. Volume 44:Issue 18(2017)
• Page Start: 9225
• Page End: 9232
• Publication Date: 2017-09-22
• Subjects: Juno/Waves -- ExPRES -- Jupiter -- Io -- radio -- decametric; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL073036
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We compare observations from the Juno/Waves radio experiment with simulations of radio «arcs» in the time‐frequency plane resulting from the Io‐Jupiter interaction, performed with the ExPRES code. We identify the hemisphere of origin of the observed arcs directly from simulations and confirm this identification through comparison with Juno, Nançay, and Wind observations. The occurrence and shape of observed arcs are well modeled, at low latitudes with their usual shapes as seen from Earth, as well as at high latitudes with longer, bowl‐shaped, arcs observed for the first time. Predicted emission is actually observed only when the radio beaming angle θ = (k, B ) ≥ 70° ± 5°, providing new constraints on the generation of the decameter emission by the Cyclotron Maser Instability. Further improvements of ExPRES are outlined, which will then be applied to Juno and Earth‐based observations of radio emissions induced by other Galilean satellites or associated to the main auroral oval. Key Points: First Juno/Waves observations compared to ExPRES simulations of Jupiter‐Io decametric emission Near equator ExPRES simulations show that most of the arcs observed in the time‐frequency plane by Juno, Wind, and Nançay are due to Io The simulations and observations of Io arcs are in good agreement when the modeled radio beaming angle θ = (k, B ) ≥ 70° ± 5°