Large‐scale solar wind flow around Saturn's nonaxisymmetric magnetosphere
- 3 September 2017
- journal article
- research article
- Published by American Geophysical Union (AGU) in Journal of Geophysical Research: Space Physics
- Vol. 122 (9) , 9198-9206
Abstract
The interaction between the solar wind and a magnetosphere is central to the dynamics of a planetary system. Here we address fundamental questions on the large‐scale magnetosheath flow around Saturn using a 3‐D magnetohydrodynamic (MHD) simulation. We find Saturn's polar‐flattened magnetosphere to channel ~20% more flow over the poles than around the flanks at the terminator. Further, we decompose the MHD forces responsible for accelerating the magnetosheath plasma to find the plasma pressure gradient as the dominant driver. This is by virtue of a high‐β magnetosheath and, in turn, the high‐MA bow shock. Together with long‐term magnetosheath data by the Cassini spacecraft, we present evidence of how nonaxisymmetry substantially alters the conditions further downstream at the magnetopause, crucial for understanding solar wind‐magnetosphere interactions such as reconnection and shear flow‐driven instabilities. We anticipate our results to provide a more accurate insight into the global conditions upstream of Saturn and the outer planets.Keywords
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Funding Information
- National Aeronautics and Space Administration (1415150)
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