Variability of Jupiter's IR H3+ aurorae during Juno approach

L Moore, J O'Donoghue, H Melin… - Geophysical …, 2017 - Wiley Online Library
L Moore, J O'Donoghue, H Melin, T Stallard, C Tao, B Zieger, J Clarke, MF Vogt
Geophysical Research Letters, 2017Wiley Online Library
We present ground‐based observations of Jupiter's H3+ aurorae over four nights in April
2016 while the Juno spacecraft was monitoring the upstream interplanetary magnetic field.
High‐precision maps of auroral H3+ densities, temperatures, and radiances reveal
significant variabilities in those parameters, with regions of enhanced density and emission
accompanied by reduced temperature. Juno magnetometer data, combined with solar wind
propagation models, suggest that a shock may have impacted Jupiter in the days preceding …
Abstract
We present ground‐based observations of Jupiter's H3+ aurorae over four nights in April 2016 while the Juno spacecraft was monitoring the upstream interplanetary magnetic field. High‐precision maps of auroral H3+ densities, temperatures, and radiances reveal significant variabilities in those parameters, with regions of enhanced density and emission accompanied by reduced temperature. Juno magnetometer data, combined with solar wind propagation models, suggest that a shock may have impacted Jupiter in the days preceding the observation interval but that the solar wind was quiescent thereafter. Auroral H3+ temperatures reveal a downward temporal trend, consistent with a slowly cooling upper atmosphere, such as might follow a period of shock recovery. The brightest H3+ emissions are from the end of the period, 23 April. A lack of definitive signatures in the upstream interplanetary magnetic field lends supporting evidence to the possibility that this brightening event may have been driven by internal magnetospheric processes.
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