Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 18, 887-896, 2000
http://www.ann-geophys.net/18/887/2000/
doi:10.1007/s00585-000-0887-z
© European Geosciences Union 2000
 
31 Aug 2000
Central polar cap convection response to short duration southward Interplanetary Magnetic Field
P. T. Jayachandran and J. W. MacDougall Department of Electrical Engineering, University of Western Ontario, London, Ontario, Canada, N6A5B9
Correspondence to: P.T. Jayachandran
Abstract. Central polar cap convection changes associated with southward turnings of the Interplanetary Magnetic Field (IMF) are studied using a chain of Canadian Advanced Digital Ionosondes (CADI) in the northern polar cap. A study of 32 short duration (~1 h) southward IMF transition events found a three stage response: (1) initial response to a southward transition is near simultaneous for the entire polar cap; (2) the peak of the convection speed (attributed to the maximum merging electric field) propagates poleward from the ionospheric footprint of the merging region; and (3) if the change in IMF is rapid enough, then a step in convection appears to start at the cusp and then propagates antisunward over the polar cap with the velocity of the maximum convection. On the nightside, a substorm onset is observed at about the time when the step increase in convection (associated with the rapid transition of IMF) arrives at the polar cap boundary.

Key words: Ionosphere (plasma convection; polar ionosphere) - Magnetospheric physics (solar wind - magnetosphere interaction)


Citation: Jayachandran, P. T. and MacDougall, J. W.: Central polar cap convection response to short duration southward Interplanetary Magnetic Field, Ann. Geophys., 18, 887-896, doi:10.1007/s00585-000-0887-z, 2000.
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