Flux closure during a substorm observed by cluster, double star, IMAGE FUV, SuperDARN, and greenland magnetometers

Milan, S. E. and Wild, J. A. and Hubert, B. and Carr, C. M. and Lucek, E. and Bosqued, J. M. and Watermann, J. F. and Slavin, J. A. (2006) Flux closure during a substorm observed by cluster, double star, IMAGE FUV, SuperDARN, and greenland magnetometers. Annales Geophysicae, 24 (2). pp. 751-767. ISSN 0992-7689

[thumbnail of art_747.pdf]
PDF (art_747.pdf)

Download (1MB)


We examine magnetic flux closure during an ex- tended substorm interval on 29 August 2004 involving a two-stage onset and subsequent re-intensifications. Cluster and Double Star provide observations of magnetotail dy- namics, while the corresponding auroral evolution, convec- tion response, and substorm current wedge development are monitored by IMAGE FUV, SuperDARN, and the Greenland magnetometer chain, respectively. The first stage of onset is associated with the reconnection of closed flux in the plasma sheet; this is accompanied by a short-lived auroral intensification, a modest substorm current wedge magnetic bay, but no significant ionospheric convection enhancement. The second stage follows the progression of reconnection to the open field lines of the lobes; accompanied by prolonged auroral bulge and westward-travelling surge development, enhanced magnetic bays and convection. We find that the tail dynamics are highly influenced by ongoing dayside creation of open flux, leading to flux pile-up in the near-tail and a step-wise down-tail motion of the tail reconnection site. In all, 5 dipolarizations are observed, each associated with the closure of ∼0.1 GWb of flux. Very simple calculations indicate that the X-line should progress down-tail at a speed of 20 km s−1, or 6 RE between each dipolarization.

Item Type:
Journal Article
Journal or Publication Title:
Annales Geophysicae
Uncontrolled Keywords:
?? dcs-publications-idart-747dcs-publications-creditsionodcs-publications-personnel-id104earth and planetary sciences (miscellaneous)astronomy and astrophysicsatmospheric sciencegeologyspace and planetary sciencet technology (general) ??
ID Code:
Deposited By:
Deposited On:
21 Apr 2008 11:08
Last Modified:
07 Jul 2024 23:21