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GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L03104, doi:10.1029/2007GL032460, 2008

Auroral polar dawn spots: Signatures of internally driven reconnection processes at Jupiter's magnetotail

A. Radioti

Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique, Université de Liège, Liege, Belgium


D. Grodent

Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique, Université de Liège, Liege, Belgium


J.-C. Gérard

Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique, Université de Liège, Liege, Belgium


B. Bonfond

Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique, Université de Liège, Liege, Belgium


J. T. Clarke

Center for Space Physics, Boston University, Boston, Massachusetts, USA


Abstract

We report the presence of polar spots located in the dawn auroral region, based on the HST ACS 2007 campaign. We study the location of these features in the equatorial plane as well as their time scales and periodicities, based on a comprehensive series of images taken between February 21 and June 11, 2007. It is shown that the majority of polar dawn spots magnetically map to the dawn sector. Additionally, they occur quasi-periodically every 2–3 days, a periodicity observed for the first time in auroral features. Because of their mapped location and their periodic cycle, we interpret the polar dawn spots as signatures of internally driven magnetic reconnection in the Jovian magnetotail.

Received 25 October 2007; accepted 31 December 2007; published 7 February 2008.

Keywords: aurora; reconnection; Jovian substorms.

Index Terms: 2407 Ionosphere: Auroral ionosphere (2704); 2723 Magnetospheric Physics: Magnetic reconnection (7526, 7835); 2790 Magnetospheric Physics: Substorms; 2744 Magnetospheric Physics: Magnetotail; 2736 Magnetospheric Physics: Magnetosphere/ionosphere interactions (2431).

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 318145 bytes)

Citation: Radioti, A., D. Grodent, J.-C. Gérard, B. Bonfond, and J. T. Clarke (2008), Auroral polar dawn spots: Signatures of internally driven reconnection processes at Jupiter's magnetotail, Geophys. Res. Lett., 35, L03104, doi:10.1029/2007GL032460.