Observations of Jupiter’s Auroral X-ray Emission coinciding with a Coronal Mass Ejection
Magnetic fields of planets and cool stars
William Dunn
UCL/ Mullard Space Science Laboratory
G. Branduardi-Raymont (UCL/MSSL), A. J. Coates(UCL/MSSL), R. Elsner (NASA Marshall Space Flight Centre), M. F. Vogt (Boston University), P. G. Ford (MIT), J. D. Nichols (University of Leicester), L. Lamy (LESIA, Observatoire de Paris),
We report changes in the brightness, periodic behaviour, spatial distribution and spectra of Jupiter‘s Northern X-ray Aurora from two Chandra observations, one during and one following the arrival of a Coronal Mass Ejection (CME) at the planet. During the first observation, coincident with the CME arrival, we observe a bright auroral enhancement by a factor of ∼8 in a normally dim region, which occurs shortly before a hectometric radio burst.

We use Vogt et al. [2011] Jovian magnetic field models to infer the source of the ions producing the X-ray aurora and map them to both the magnetosphere and the solar wind. We also map emission to 50-90RJ from precipitation of possible magnetospheric sulphur ions, as suggested by Cravens et al. [2003].

Gladstone et al. [2002] discovered an auroral X-ray hot spot that pulsated with 45 minute periodicity. We also observe periodicities during the first observation on timescales of 11-13 and 26-28 minutes. Carbon/sulphur emission features a strong 26-28 minute period, while oxygen emission does not. These differing periodicities support spatial mapping suggesting different source origins for oxygen and carbon/sulphur emission. The second observation features 40-50 minute periodicity.

We find that most emission from the hot spot occurs when field lines would be opening and closing in this region and maps to magnetospheric local times between 10:30-18:00 hours. This combination of mapping with periodic pulsing and emission along the open-closed field line boundary may indicate that during high solar wind pressure the Jovian X-ray aurora is linked to dayside reconnection.
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