Abstract
The role of high-speed solar wind streams in driving relativistic electron acceleration within the Earth's magnetosphere during solar activity minimum conditions has been well documented. The rising phase of the new solar activity cycle (cycle 23) commenced in 1996, and there have recently been a number of coronal mass ejections (CMEs) and related “magnetic clouds” at 1 AU. As these CME/cloud systems interact with the Earth's magnetosphere, some events produce substantial enhancements in the magnetospheric energetic particle population while others do not. This paper compares and contrasts relativistic electron signatures observed by the POLAR, SAMPEX, Highly Elliptical Orbit, and geostationary orbit spacecraft during two magnetic cloud events: May 27–29, 1996, and January 10–11, 1997. Sequences were observed in each case in which the interplanetary magnetic field was first strongly southward and then rotated northward. In both cases, there were large solar wind density enhancements toward the end of the cloud passage at 1 AU. Strong energetic electron acceleration was observed in the January event, but not in the May event. The relative geoeffectiveness for these two cases is assessed, and it is concluded that large induced electric fields (∂B/∂t) caused in situ acceleration of electrons throughout the outer radiation zone during the January 1997 event.
Department
Physics
Publication Date
8-1-1998
Journal Title
Journal of Geophysical Research: Space Physics
Publisher
American Geophysical Union
Digital Object Identifier (DOI)
10.1029/97JA03329
Document Type
Article
Recommended Citation
Baker, D. N., T. I. Pulkkinen, X. Li, S. G. Kanekal, J. B. Blake, R. S. Selesnick, M. G. Henderson, G. D. Reeves, H. E. Spence, and G. Rostoker (1998), Coronal mass ejections, magnetic clouds, and relativistic magnetospheric electron events: ISTP, J. Geophys. Res., 103(A8), 17279–17291, doi:10.1029/97JA03329.
Rights
Copyright 1998 by the American Geophysical Union.