Abstract
To help understand and determine the driver of jovian auroral X-rays, we
present the first statistical study to focus on the morphology and
dynamics of the jovian northern hot spot (NHS) using Chandra data. The
catalogue we explore dates from 18 December 2000 up to and including 8
September 2019. Using a numerical criterion, we characterize the typical
and extreme behaviour of the concentrated NHS emissions across the
catalogue. The mean power of the NHS is found to be 1.91 GW with a
maximum brightness of 2.02 Rayleighs (R), representing by far the
brightest parts of the jovian X-ray spectrum. We report a statistically
significant region of emissions at the NHS center which is always
present, the averaged hot spot nucleus (AHSNuc), with mean power of 0.57
GW and inferred average brightness of ∼ 1.2 R. We use a flux equivalence
mapping model to link this distinct region of X-ray output to a likely
source location and find that the majority of mappable NHS photons
emanate from the pre-dusk to pre-midnight sector, coincident with the
dusk flank boundary. A smaller cluster maps to the noon magnetopause
boundary, dominated by the AHSNuc, suggesting that there may be multiple
drivers of X-ray emissions. On application of timing analysis techniques
(Rayleigh, Monte Carlo, Jackknife), we identify several instances of
statistically significant quasi-periodic oscillations (QPOs) in the NHS
photons ranging from ∼ 2.3-min to 36.4-min, suggesting possible links
with ultra-low frequency activity on the magnetopause boundary (e.g.
dayside reconnection, Kelvin-Helmholtz instabilities).