Publication Date:
2016-01-31
Description:
We report the first Jupiter X-ray observations planned to coincide with an Interplanetary Coronal Mass Ejection (ICME). At the predicted ICME arrival time, we observed a factor of ∼8 enhancement in Jupiter‘s X-ray aurora. Within 1.5 hours of this enhancement, intense bursts of non-Io decametric radio emission occurred. Spatial, spectral and temporal characteristics also varied between ICME arrival and another X-ray observation two days later. Gladstone et al. [2002] discovered the polar X-ray hot spot and found it pulsed with 45minute quasi-periodicity. During the ICME arrival, the hot spot expanded and exhibited two periods: 26minute periodicity from sulfur ions and 12minute periodicity from a mixture of carbon/sulfur and oxygen ions. After the ICME, the dominant period became 42minutes. By comparing Vogt et al. [2011] Jovian mapping models with spectral analysis, we found that during ICME arrival at least two distinct ion populations, from Jupiter‘s dayside, produced the X-ray aurora. Auroras mapping to magnetospheric field lines between 50-70R J were dominated by emission from precipitating sulfur ions (S 7+,...,14+ ). Emissions mapping to closed field lines between 70-120R J and to open field lines were generated by a mixture of precipitating oxygen (O 7+,8+ ) and sulfur/carbon ions, possibly implying some solar wind precipitation. We suggest the best explanation for the X-ray hot spot is pulsed dayside reconnection perturbing magnetospheric downward currents, as proposed by Bunce et al. [2004]. The auroral enhancement has different spectral, spatial and temporal characteristics to the hot spot. By analysing these characteristics and coincident radio emissions, we propose that the enhancement is driven directly by the ICME through Jovian magnetosphere compression and/or a large-scale dayside reconnection event.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
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