The contribution of planetary period oscillations towards circulation and mass loss in Saturn’s magnetosphere
Author(s)
Agiwal, Omakshi
Masters, Adam
Hunt, Greg
Dougherty, Michele
Type
Journal Article
Abstract
Magnetic reconnection is a process during which magnetic energy is released as kinetic energy. It is considered a crucial driver of energy transport and mass loss within Saturn's magnetosphere. On long-term timescales, is thought to be predominantly driven by the rapid rotation of equatorially mass-loaded flux tubes (i.e., the Vasyliunas cycle), but there is some non-negligible driving from the solar wind as well (i.e., the Dungey cycle). In this study, we investigate an atmospheric driven phenomenon that modulates Saturn's magnetosphere every ∼10.6–10.8 hr, known as planetary period oscillations (PPOs), as an additional driver of magnetic reconnection at Saturn. Using an empirical model of PPO dynamics and Cassini magnetic field and plasma measurements, we find that PPO-driven magnetic reconnection is likely to occur in Saturn's magnetosphere, however, the occurrence of the phenomenon depends on temporally variable characteristics of the PPO systems and spatial asymmetries within Saturn's equatorial magnetosphere. Thus, it is not expected to be an on-going process. On year-long timescales, we find that PPOs are expected to be on par with the Dungey Cycle in driving circulation within Saturn's magnetosphere. However, on ∼1–2 weeks-long timescales, under specific conditions where PPO-driven reconnection is expected to be active, this phenomenon can become more significant than the Vasyliunas cycle, and thus dominate circulation within Saturn's magnetosphere. On year-long timescales, this process is estimated to remove upwards of ∼20% of the mass loaded into the magnetosphere by Enceladus.
Date Issued
2022-06
Date Acceptance
2022-05-27
Citation
Journal of Geophysical Research: Space Physics, 2022, 127 (6), pp.1-17
ISSN
2169-9380
Publisher
American Geophysical Union
Start Page
1
End Page
17
Journal / Book Title
Journal of Geophysical Research: Space Physics
Volume
127
Issue
6
Copyright Statement
©2022. 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.
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.
License URL
Sponsor
The Royal Society
The Royal Society
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022JA030439
Grant Number
UF150547
URF\R\211012
Subjects
0201 Astronomical and Space Sciences
0401 Atmospheric Sciences
Publication Status
Published
Date Publish Online
2022-06-02