Jovian Auroral X-ray Emission Coinciding with an Interplanetary Coronal Mass Ejection

The extent of the Solar Wind influence on Jupiter's X-ray aurora is yet to be understood. To probe this relationship, we compare two Chandra X-ray observations of Jupiter: one coinciding with the predicted arrival of an Interplanetary Coronal Mass Ejection (ICME) and another observation two days later. During the observation coincident with the ICME, we observe a bright auroral enhancement of a factor of 8 in a region normally absent of X-rays. This enhancement occurs ~1 hour before a burst of non-Io Decametric radio emission, believed to be associated with solar wind forward shocks [Hess et al. 2012, 2014]. We also find variation in X-ray auroral periodic behaviour, spatial and spectral distributions. We use magnetosphere-ionosphere mapping [Vogt et al. 2011] to identify the source of ions generating the X-rays and find that they originate from 10:30-18:00 magnetospheric local time (MLT) in regions of the outer magnetosphere close to the magnetopause. The model also maps some precipitation to open field lines. This suggests that X-rays may provide an excellent tool for analysing the Jovian outer magnetosphere and the processes occurring between the Jovian magnetopause and the solar wind. As discovered by Gladstone et al. [2002] discovery, we find an X-ray hot spot that pulses with quasi-periodicity. Measurements of this periodicity suggest 2 distinct ion populations generate the Jovian X-ray aurora: a sulphur/carbon dominated population from the middle to outer magnetosphere with a period of 26 minutes, and a combined oxygen and carbon/sulphur population from close to the magnetopause with a period of 12 minutes. The source region and periodicity support findings by Bunce et al. [2004] that pulsed dayside reconnection could energise the outer magnetosphere and drive X-ray emission To better understand the persistence of these features and/or their relationship to the ICME, we compare these 2011 observations with preliminary analysis of Chandra X-ray observations of Jupiter from 2007. At this time, New Horizons was approaching the planet. We hope that this will provide a useful analogy for the Spring 2016 Juno approach.