Saturn's planetary period oscillations during the closest approach of Cassini's ring grazing orbits
File(s)Hunt_et_al-2018-Geophysical_Research_Letters.pdf (1.28 MB)
Published version
Author(s)
Hunt, GJ
Provan, G
Cowley, SWH
Dougherty, MK
Southwood, DJ
Type
Journal Article
Abstract
Saturn's planetary period oscillations (PPOs) are ubiquitous throughout its magnetosphere. We investigate the PPO's azimuthal magnetic field amplitude interior to the field‐aligned currents, during the closest approaches of Cassini's ring‐grazing orbits (October 2016 to April 2017), with periapses at ~2.5 RS. The amplitudes of the northern and southern PPO systems are shown to vary as a function of latitude. The amplitude ratio between the two PPO systems shows that the northern system is dominant by a factor of ~1.3 in the equatorial plane, and it is dominant to ~ −15° latitude in the southern hemisphere. The dayside amplitudes are approximately half of the 2008 nightside amplitudes, which agree with previous local time‐related amplitude observations. Overall, there is clear evidence that the PPOs are present on field lines that map to the outer edge of Saturn's rings, closer to Saturn than previously confirmed.
Date Issued
2018-05-28
Date Acceptance
2018-05-06
Citation
Geophysical Research Letters, 45 (10), pp.4692-4700
ISSN
0094-8276
Publisher
American Geophysical Union
Start Page
4692
End Page
4700
Journal / Book Title
Geophysical Research Letters
Volume
45
Issue
10
Copyright Statement
©2018. The Authors.
This is an open access article under the
terms of the Creative Commons
Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use,
distribution and reproduction in any
medium, provided the original work is
properly cited.
This is an open access article under the
terms of the Creative Commons
Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use,
distribution and reproduction in any
medium, provided the original work is
properly cited.
Sponsor
Science and Technology Facilities Council (STFC)
The Royal Society
Science and Technology Facilities Council (STFC)
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL077925
Grant Number
ST/N000692/1
RP140004
ST/P006922/1
Subjects
Science & Technology
Physical Sciences
Geosciences, Multidisciplinary
Geology
Saturn
periodicities
magnetosphere
amplitudes
current systems
oscillations
UPPER-ATMOSPHERE
MAGNETOSPHERE
PERIODICITIES
NORTHERN
SYSTEMS
FIELD
MD Multidisciplinary
Meteorology & Atmospheric Sciences
Publication Status
Published
Date Publish Online
2018-05-11