Determining the nominal thickness and variability of the magnetodisc current sheet at saturn
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Published version
Author(s)
Staniland, Ned
Dougherty, Michele
Masters, Adam
Bunce, Emma
Type
Journal Article
Abstract
The thickness and variability of the Saturnian magnetodisc current sheet is investigated using the Cassini magnetometer data set. Cassini performed 66 fast, steep crossings of the equatorial current sheet where a clear signature in the magnetic field data allowed for a direct determination of its thickness and the offset of its center. The average, or nominal, current sheet half‐thickness is 1.3 R S , where R S is the equatorial radius of Saturn, equal to 60,268 km. This is thinner than previously calculated, but both spatial and temporal dependencies are identified. The current sheet is thicker and more variable by a factor ∼2 on the nightside compared to the dayside, ranging from 0.5–3 R S . The current sheet is on average 50% thicker in the nightside quasi‐dipolar region (≤15 R S ) compared to the dayside. These results are consistent with the presence of a noon‐midnight electric field at Saturn that produces a hotter plasma population on the nightside compared to the dayside. It is also shown that the current sheet becomes significantly thinner in the outer region of the nightside, while staying approximately constant with radial distance on the dayside, reflecting the dayside compression of the magnetosphere by the solar wind. Some of the variability is well characterized by the planetary period oscillations (PPOs). However, we also find evidence for non‐PPO drivers of variability.
Date Issued
2020-05
Date Acceptance
2020-04-08
Citation
Journal of Geophysical Research: Space Physics, 2020, 125 (5), pp.1-15
ISSN
2169-9380
Publisher
American Geophysical Union
Start Page
1
End Page
15
Journal / Book Title
Journal of Geophysical Research: Space Physics
Volume
125
Issue
5
Copyright Statement
©2020. The Authors.
This is an open access article under the terms of the Creative Commons Attribution License (http://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 (http://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Sponsor
The Royal Society
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020JA027794
Grant Number
UF150547
Subjects
0201 Astronomical and Space Sciences
0401 Atmospheric Sciences
Publication Status
Published
Date Publish Online
2020-04-16