Coordinated ground-based, low altitude satellite and Cluster observations on global and local scales during a transient post-noon sector excursion of the magnetospheric cusp

H. J. Opgenoorth (1, 2) , M. Lockwood (3) , D. Alcaydé (4) , E. Donovan (5) , M. J. Engebretson (6) , A. P. van Eyken (7) , K. Kauristie (2) , M. Lester (8) , J. Moen (9) , J. Waterman (10) , H. Alleyne (11) , M. André (1) , M. W. Dunlop (12) , N. Cornilleau-Wehrlin (13) , A. Masson (14) , A. Fazerkerley (15) , H. Rème (4) , R. André (14) , O. Amm (2) , A. Balogh (12) , R. Behlke (1) , P. L. Blelly (4) , H. Boholm (7) , E. Borälv (1) , J. M. Bosqued (4) , S. Buchert (1) , M. Candidi (16) , J. C. Cerisier (13) , C. Cully (1, 5) , W. F. Denig (17) , P. Eglitis (1) , R. A. Greenwald (18) , B. Jackal (5) , J. D. Kelly (19) , I. Krauklis (15) , G. Lu (20) , I. R. Mann (21) , M. F. Marcucci (16) , I. W. Mccrea (3) , M. Maksimovic (13) , S. Massetti (16) , Pierrette Décréau (22) , D. K. Milling (21) , S. Orsini (16) , F. Pitout (1, 4) , G. Provan (8) , J. M. Ruohoniemi (18) , J. C. Samson (23) , J. J. Schott (24) , F. Sedgemore-Schulthess (25) , R. Stamper (3) , P. Stauning (10) , A. Strømme (26) , M. Taylor (15) , A. Vaivads (1) , J. P. Villain (14) , I. Voronkov (23) , J. A. Wild (8) , M. Wild (3)

1 IRF - Swedish Institute of Space Physics [Kiruna]
2 FMI - Finnish Meteorological Institute
3 RAL - STFC Rutherford Appleton Laboratory
4 CESR - Centre d'étude spatiale des rayonnements
5 Department of Physics and Astronomy [Calgary]
6 Department of Physics [Minneapolis]
7 EISCAT Scientific Association [Norway]
8 University of Leicester
9 UiO - University of Oslo
10 DMI - Danish Meteorological Institute
11 University of Sheffield [Sheffield]
12 Imperial College London
13 CETP - Centre d'étude des environnements terrestre et planétaires
14 ESTEC - European Space Research and Technology Centre
15 MSSL - Mullard Space Science Laboratory
16 IFSI - Istituto di Fisica dello Spazio Interplanetario
17 AFRL - Air Force Research Laboratory
18 APL - Johns Hopkins University Applied Physics Laboratory [Laurel, MD]
19 SRI - SRI International [Menlo Park]
20 NCAR - National Center for Atmospheric Research [Boulder]
21 University of York [York, UK]
22 LPCE - Laboratoire de physique et chimie de l'environnement
23 University of Alberta
24 EOST - Ecole et Observatoire des sciences de la terre
25 DSRI - Danish Space Research Institute
26 UiT - University of Tromsø

On 14 January 2001, the four Cluster spacecraft passed through the northern magnetospheric mantle in close conjunction to the EISCAT Svalbard Radar (ESR) and approached the post-noon dayside magnetopause over Green-land between 13:00 and 14:00 UT. During that interval, a sudden reorganisation of the high-latitude dayside convection pattern occurred after 13:20 UT, most likely caused by a direction change of the Solar wind magnetic field. The result was an eastward and poleward directed flow-channel, as monitored by the SuperDARN radar network and also by arrays of ground-based magnetometers in Canada, Greenland and Scandinavia. After an initial eastward and later poleward expansion of the flow-channel between 13:20 and 13:40 UT, the four Cluster spacecraft, and the field line footprints covered by the eastward looking scan cycle of the Söndre Strömfjord incoherent scatter radar were engulfed by cusp-like precipitation with transient magnetic and electric field signatures. In addition, the EISCAT Svalbard Radar detected strong transient effects of the convection reorganisation, a poleward moving precipitation, and a fast ion flow-channel in association with the auroral structures that suddenly formed to the west and north of the radar. From a detailed analysis of the coordinated Cluster and ground-based data, it was found that this extraordinary transient convection pattern, indeed, had moved the cusp precipitation from its former pre-noon position into the late post-noon sector, allowing for the first and quite unexpected encounter of the cusp by the Cluster spacecraft. Our findings illustrate the large amplitude of cusp dynamics even in response to moderate solar wind forcing. The global ground-based data proves to be an invaluable tool to monitor the dynamics and width of the affected magnetospheric regions.

Domaines: Océan, Atmosphère; Sciences de la Terre

H. J. Opgenoorth, M. Lockwood, D. Alcaydé, E. Donovan, M. J. Engebretson, et al.. Coordinated ground-based, low altitude satellite and Cluster observations on global and local scales during a transient post-noon sector excursion of the magnetospheric cusp. Annales Geophysicae, 2001, 19 (10/12), pp.1367-1398. ⟨hal-00329197⟩