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Diverse Electron and Ion Acceleration Characteristics Observed Over Jupiter's Main Aurora
Journal article   Open access   Peer reviewed

Diverse Electron and Ion Acceleration Characteristics Observed Over Jupiter's Main Aurora

B. H. Mauk, D. K. Haggerty, C. Paranicas, G. Clark, P. Kollmann, A. M. Rymer, J. M. Peachey, S. J. Bolton, S. M. Levin, A. Adriani, …
Geophysical research letters, Vol.45(3), pp.1277-1285
02/16/2018
DOI: 10.1002/2017GL076901
url
https://doi.org/10.1002/2017GL076901View
Published (Version of record) Open Access

Abstract

Two new Juno‐observed particle features of Jupiter's main aurora demonstrate substantial diversity of processes generating Jupiter's mysterious auroral emissions. It was previously speculated that sometimes‐observed potential‐driven aurora (up to 400 kV) can turn into broadband stochastic acceleration (dominating at Jupiter) by means of instability. Here direct evidence for such a process is revealed with a “mono‐energetic” electron inverted‐V rising in energy to 200 keV, transforming into a region of broadband acceleration with downward energy fluxes tripling to 3,000 mW/m2, and then transforming back into a mono‐energetic structure ramping down from 200 keV. But a second feature of interest observed nearby is unlikely to have operated in the same way. Here a downward accelerated proton inverted‐V, with inferred potentials to 300–400 kV, occurred simultaneously with downward accelerated broadband electrons with downward energy fluxes as high as any observed (~3,000 mW/m2). This latter feature has no known precedent with Earth auroral observations. Key Points Two new particle features are identified within the intense auroral acceleration regions at Jupiter demonstrating great diversity One feature supports a hypothesis that potential‐driven aurora can become unstable and convert over to broadband, stochastic acceleration The other feature contradicts that hypothesis and has no qualitative precedent within Earths' auroral acceleration regions
aurora energetic particles Juno Jupiter magnetosphere

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