Global manifestations of a substorm onset observed by a multi-satellite and ground station network

H. Wang (1) , S. Y. Ma (1) , H. Lühr (2) , Z. X. Liu (3) , Z. Y. Pu (4) , C. P. Escoubet (5) , H. U. Frey (6) , H. Réme (7) , P. Ritter (2)

1 Inst. of Ionosphere and Magnetosphere
2 GFZ - German Research Centre for Geosciences - Helmholtz-Centre Potsdam
3 CSSAR - Center for Space Science and Applied Research [Beijing]
4 School of Earth and Space Sciences [Beijing]
5 ESTEC - European Space Research and Technology Centre
6 SSL - Space Sciences Laboratory [Berkeley]
7 CESR - Centre d'étude spatiale des rayonnements

With a favorable constellation of spacecraft and ground stations, a study is made on the global manifestations of a substorm onset. The onset occurred simultaneously and conjugately in both hemispheres, confirmed by observations of the auroral breakup from IMAGE FUV-WIC and a sudden intensification of a westward electrojet from ground-based magnetometers. Concurrently with the onset, field-aligned and Hall currents in the auroral ionosphere are observed by CHAMP, which are consistent with the signature of a Harang discontinuity. Immediately after the onset a magnetic field dipolarization is clearly observed by Double Star TC-1, located near the central magnetotail and subsequently, by the Cluster quartet. The observations can be explained by a dawnward propagation of the substorm current wedge at a speed of about 300 km/s.

Domaines: Océan, Atmosphère; Sciences de la Terre

H. Wang, S. Y. Ma, H. Lühr, Z. X. Liu, Z. Y. Pu, et al.. Global manifestations of a substorm onset observed by a multi-satellite and ground station network. Annales Geophysicae, 2006, 24 (12), pp.3491-3496. ⟨hal-00330105⟩