American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 643413 bytes)    Cited by

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. A10, 1289, doi:10.1029/2001JA007553, 2002

Relationship between multiple substorm onsets and the IMF: A case study

C.-C. Cheng

Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California, USA


C. T. Russell

Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California, USA


M. Connors

Centre for Science, Athabasca University, Athabasca, Alberta, Canada


P. J. Chi

Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California, USA


Abstract

The relationship between a series of Pi2 pulsations and their associated substorm onsets with the IMF is examined on 5 May 1999. The magnetograms from the CANOPUS array show the occurrence of three substorm onsets, accompanied by Pi2 bursts. Analysis of the auroral electrojet location and current intensity as deduced from the Churchill line in the CANOPUS array shows that the following onsets move poleward. ACE and Wind magnetic field data show that the first onset occurs during a period of weak southward interplanetary magnetic field (IMF) and that the second onset occurs about an hour later when the IMF has become slightly northward. The third onset occurs during strongly northward IMF. Magnetic disturbances at GOES 8 and GOES 10 confirm that each onset is accompanied by disturbances in the field like those expected from the substorm current wedge. Meanwhile, from the IMP 8 observations in the magnetotail, the decreases of the total and X components of the magnetic field imply that significant removal of magnetic flux from the tail has occurred after the third onset. Thus a single cycle of dayside reconnection transport of open flux and reconnection of that open flux may contain within it multiple onsets of tail reconnection and dipolarization of the night magnetosphere, some possibly not involving the open flux in the lobes.

Published 10 October 2002.

Index Terms: 2788 Magnetospheric Physics: Storms and substorms; 2752 Magnetospheric Physics: MHD waves and instabilities; 2740 Magnetospheric Physics: Magnetospheric configuration and dynamics.

Read Full Article (file size: 643413 bytes)    Cited by

Citation: Cheng, C.-C., C. T. Russell, M. Connors, and P. J. Chi (2002), Relationship between multiple substorm onsets and the IMF: A case study, J. Geophys. Res., 107(A10), 1289, doi:10.1029/2001JA007553.