Saturn's planetary period oscillations during the closest approach of Cassini's ring grazing orbits

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Title: Saturn's planetary period oscillations during the closest approach of Cassini's ring grazing orbits
Author(s): Hunt, GJ
Provan, G
Cowley, SWH
Dougherty, MK
Southwood, DJ
Item 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.
Publication Date: 28-May-2018
Date of Acceptance: 6-May-2018
URI: http://hdl.handle.net/10044/1/59864
DOI: https://dx.doi.org/10.1029/2018GL077925
ISSN: 0094-8276
Publisher: American Geophysical Union
Journal / Book Title: Geophysical Research Letters
Sponsor/Funder: Science and Technology Facilities Council (STFC)
Funder's Grant Number: ST/N000692/1
Copyright Statement: ©2018. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Keywords: MD Multidisciplinary
Meteorology & Atmospheric Sciences
Publication Status: Published online
Online Publication Date: 2018-05-11
Appears in Collections:Space and Atmospheric Physics
Physics
Faculty of Natural Sciences



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