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Characteristics of pseudobreakups and substorms observed in the ionosphere, at the geosynchronous orbit, and in the midtail
- Source :
- Journal of Geophysical Research: Space Physics. 104:12263-12287
- Publication Year :
- 1999
- Publisher :
- American Geophysical Union (AGU), 1999.
-
Abstract
- We present a comprehensive study of a sequence of two substorms and multiple pseudobreakups using optical, magnetic and incoherent scatter radar measurements, energetic particles from two geosynchronous satellites and particle and field data from the Geotail spacecraft located at Xgsm ∼ −86 RE. Following conventional nomenclature, we classified as pseudobreakups those auroral breakups which did not exhibit significant poleward expansion (< 2° magnetic latitude). Auroral intensifications following substorm breakups were also observed, and were classified separately. Pseudobreakups were found not to differ from substorm breakups in longitudinal extent (from 1.3 to 6.1 hours of magnetic local time), or in duration (from 5 to 16 minutes). In general, the ionospheric currents producing ground magnetic disturbances were more intense during substorms than pseudobreakups. We found that pseudobreakups are associated with the same magnetospheric processes as substorm breakups which involve current wedge formation, midlatitude magnetic Pi2 pulsations and energetic particle injections at the geosynchronous altitude. Moreover, pseudobreakups are associated with magnetic reconnection in the near-Earth region, evidenced by the typical subsequent detection of a plasmoid at Geotail. This implies that the magnetotail volume influenced by a pseudobreakup is quite large in radial distance. We conclude that there is no definitive qualitative distinction between pseudobreakups and substorms but there is a continuum of states between the small pseudobreakups and large substorms.
- Subjects :
- Physics
Atmospheric Science
Ecology
Incoherent scatter
Geosynchronous orbit
Paleontology
Soil Science
Forestry
Plasmoid
Magnetic reconnection
Geophysics
Aquatic Science
Oceanography
Space and Planetary Science
Geochemistry and Petrology
Local time
Middle latitudes
Substorm
Earth and Planetary Sciences (miscellaneous)
Ionosphere
Earth-Surface Processes
Water Science and Technology
Subjects
Details
- ISSN :
- 01480227
- Volume :
- 104
- Database :
- OpenAIRE
- Journal :
- Journal of Geophysical Research: Space Physics
- Accession number :
- edsair.doi.dedup.....2c49c0ddcf1026d1bb1cb8964081e9d1