Journal
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
Volume 114, Issue -, Pages -Publisher
AMER GEOPHYSICAL UNION
DOI: 10.1029/2008JA013988
Keywords
-
Categories
Funding
- STFC [PP/E000983/1]
- Science and Technology Facilities Council [PP/E000983/1] Funding Source: researchfish
- STFC [PP/E000983/1] Funding Source: UKRI
Ask authors/readers for more resources
Previous analyses of Hubble Space Telescope (HST) images of Saturn's southern auroras obtained during two campaigns, in January 2007 and February 2008, have revealed that the auroral oval oscillates at a period close to the planetary rotation period, with its center describing an elongated ellipse of semimajor axis similar to 2 degrees colatitude aligned along the prenoon to premidnight direction. Previous analyses of Cassini magnetic field data from Saturn's near-equatorial quasi-dipolar magnetosphere have also established the presence of a rotating pattern of magnetic field perturbations near the planetary period, a phase model which has been derived from data over the interval from mid-2004 to the end of 2007, whose extrapolation is verified here for use during the February 2008 HST campaign. In this paper we compare the phases of these oscillatory phenomena and show that the southern oval displacement was directed approximately opposite to the rotating equatorial perturbation field during both HST campaign intervals. We also examine the relation of the southern oval oscillations to the periodic power modulations in Saturn kilometric radiation (SKR) and show that the southern oval was displaced sunward at SKR maxima. It is suggested that the oval displacements are related to magnetospheric field line distortions associated with the rotating magnetic field perturbations, this picture also being consistent with recently reported periodic tilting of the equatorial plasma sheet. We note, however, that this picture provides no immediate explanation for the significantly elliptical nature of the observed oval motion.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available