[en] We use a novel method to evaluate the global opening and closure of magnetic flux in the terrestrial system, and to analyse two interplanetary shock passages that occurred during magnetically quiet periods. We find that, even under these quiet conditions, where the amount of open flux was already low, the compression of the magnetotail by the shocks still created intense but short-lived bursts of flux closure reaching similar to 130 kV, comparable to values obtained shortly after a substorm onset, although no expansion phase developed. The results, supported by a global MHD simulation of the space environment, point to a trigger mechanism of flux closure directly driven by the solar wind compression, independent of the usual substorm expansion phase process.
Disciplines :
Physical, chemical, mathematical & earth Sciences: Multidisciplinary, general & others
Author, co-author :
Hubert, Benoît ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP)
Palmroth, Minna; Finnish Meteorological Institute > Space Physics Group
Laitinen, Tiera V.; Finnish Meteorological Institute > Space Physics Group
Janhunen, Pekka; Finnish Meteorological Institute > Space Physics Group
Milan, Steve E.; University of Leicester > Department of Physics & Astronomy
Grocott, Adrian; University of Leicester > Department of Physics & Astronomy
Cowley, Stanley W.H.; University of Leicester > Department of Physics & Astronomy
Pulkkinen, Tuija; Finnish Meteorological Institute > Space Physics Group
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