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Title: Bifurcations of the main auroral ring at Saturn: ionospheric signatures of consecutive reconnection events at the magnetopause
Authors: Radioti, A.
Grodent, D.
Gerard, J-C.
Milan, S. E.
Bonfond, B.
Gustin, J.
Pryor, W.
First Published: 10-Nov-2011
Publisher: American Geophysical Union (AGU); Wiley
Citation: Journal of Geophysical Research-SPACE PHYSICS, 2011, 116
Abstract: [1] This work reports for the first time on bifurcations of the main auroral ring at Saturn observed with the UVIS instrument onboard Cassini. The observation sequence starts with an intensification on the main oval, close to noon, which is possibly associated with dayside reconnection. Consecutive bifurcations appear with the onset of dayside reconnection, between 11 and 18 magnetic local time, while the area poleward of the main emission expands to lower latitudes. The bifurcations depart with time from the main ring of emission, which is related to the open-closed field line boundary. The augmentation of the area poleward of the main emission following its expansion is balanced by the area occupied by the bifurcations, suggesting that these auroral features represent the amount of newly open flux and could be related to consecutive reconnection events at the flank of the magnetopause. The observations show that the open flux along the sequence increases when bifurcations appear. Magnetopause reconnection can lead to significant augmentation of the open flux within a couple of days and each reconnection event opens ∼10% of the flux contained within the polar cap. Additionally, the observations imply an overall length of the reconnection line of ∼4 hours of local time and suggest that dayside reconnection at Saturn can occur at several positions on the magnetopause consecutively or simultaneously.
DOI Link: 10.1029/2011JA016661
ISSN: 0148-0227
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2011 by the American Geophysical Union. All rights reserved. Archived with reference to Usage Permissions granted to authors, available at
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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