High latitude circulation in giant planet magnetospheres
File(s)
Accepted version
Author(s)
Southwood, DJ
Chane, E
Type
Journal Article
Abstract
We follow-up the proposal by Cowley et al. (2004) that the plasma circulation in the magnetospheres of the giant planets is a combination of two cycles or circulation systems. The Vasyliunas cycle transports heavy material ionized deep within the magnetosphere eventually to loss in the magnetotail. The second cycle is driven by magnetic reconnection between the planetary and the solar wind magnetic fields (the Dungey cycle) and is found on flux tubes poleward of those of the Vasyliunas cycle. We examine features of the Dungey system, particularly what occurs out of the equatorial plane. The Dungey cycle requires reconnection on the dayside, and we suggest that at the giant planets the dayside reconnection occurs preferentially in the morning sector. Second, we suggest that most of the solar wind material that enters through reconnection on to open flux tubes on the dayside never gets trapped on closed field lines but makes less than one circuit of the planet and exits down tail. In its passage to the nightside, the streaming ex-solar wind material is accelerated centrifugally by the planetary rotation primarily along the field; thus, in the tail it will appear very like a planetary wind. The escaping wind will be found on the edges of the tail plasma sheet, and reports of light ion streams in the tail are likely due to this source. The paper concludes with a discussion of high-latitude circulation in the absence of reconnection between the solar wind and planetary field.
Date Issued
2016-06-28
Date Acceptance
2016-06-03
Citation
Journal of Geophysical Research: Space Physics, 2016, 121 (6), pp.5394-5403
ISSN
2169-9402
Publisher
American Geophysical Union
Start Page
5394
End Page
5403
Journal / Book Title
Journal of Geophysical Research: Space Physics
Volume
121
Issue
6
Copyright Statement
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
Science and Technology Facilities Council (STFC)
Grant Number
ST/K001051/1
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
MAGNETIC-FIELD
MAGNETOPAUSE
RECONNECTION
MAGNETOTAIL
SATURN
JUPITER
EARTHS
WIND
CUSP
Publication Status
Published