Please use this identifier to cite or link to this item:
Title: Cassini VIMS observations of H3+ emission on the nightside of Jupiter
Authors: Stallard, Tom S.
Melin, Henrik
Miller, S.
Badman, S. V.
Baines, K. H.
Brown, R. H.
Blake, James S. D.
O'Donoghue, J.
Johnson, Rosie E.
Bools, Bethany
Pilkington, N. M.
East, Oliver T. L.
Fletcher, Mark
First Published: 2015
Publisher: American Geophysical Union (AGU), Wiley
Citation: Journal of Geophysical Research 2015
Abstract: We present the first detailed analysis of H3+ nightside emission from Jupiter, using data from the Cassini flyby in 2000-2001, producing the first jovian maps of nightside H3+ emission, temperature and column density. Using these, we identify and characterise regions of H3+ nightside emission, compared against past observations of H3+ emission on the dayside. We focus our investigation on the region previously described as ‘mid-to-low latitude emission’, the source for which has been controversial. We find that the brightest of this emission is generated at jovigraphic latitudes similar to the most equatorward extent of the main auroral emission, but concentrated at longitudes eastward of this emission. The emission is produced by enhanced H3+ density, with temperatures dropping away in this region. This emission has a loose association with the predicted location of diffuse aurora produced by pitch angle scattering in the north, but not in the south. This emission also lays in the path of sub-rotating winds flowing from the aurora, suggesting a transport origin. Some differences are seen between dayside and nightside sub-auroral emission, with dayside emission extending more equatorward, perhaps caused by the lack of sunlight ionisation on the nightside, and unmeasured changes in temperature. Ionospheric temperatures are hotter in the polar region (~1100-1500K), dropping away towards the equator (as low as 750K), broadly similar to values on the dayside, highlighting the dominance of auroral effects in the polar region. No equatorial emission is observed, suggesting that very little particle precipitation occurs away from the polar regions.
DOI Link: 10.1002/2015JA021097
ISSN: 0148-0227
eISSN: 2156-2202
Version: Post-print
Status: Peer-reviewed
Type: Journal Article
Rights: Archived with reference to SHERPA/RoMEO and publisher website. Publisher's version/PDF must be used in Institutional Repository 6 months after publication.
Description: The Cassini/VIMS data used for this paper is available from the NASA Planetary Data System.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

Files in This Item:
File Description SizeFormat 
jupiter_nightside_revision1.pdfPost-review (final submitted)6.64 MBAdobe PDFView/Open

Items in LRA are protected by copyright, with all rights reserved, unless otherwise indicated.