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Author Providakes, J. F. ♦ Kelley, M. C. ♦ Swartz, W. E. ♦ Mendillo, M. ♦ Holt, J. M.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ IONOSPHERE ♦ ELECTRIC FIELDS ♦ AURORAE ♦ AURORAL OVAL ♦ E REGION ♦ ELECTRIC CURRENTS ♦ ELECTRON DENSITY ♦ ELECTRON TEMPERATURE ♦ F REGION ♦ ION TEMPERATURE ♦ LATITUDE EFFECT ♦ MAGNETIC STORMS ♦ RADAR ♦ SATELLITES ♦ TEMPERATURE GRADIENTS ♦ CURRENTS ♦ EARTH ATMOSPHERE ♦ GEOGRAPHICAL VARIATIONS ♦ MEASURING INSTRUMENTS ♦ PLANETARY IONOSPHERES ♦ RANGE FINDERS ♦ VARIATIONS ♦ Atmospheric Physics- Auroral, Ionospheric, & Magetospheric Phenomena
Abstract Observations of very large poleward directed electric fields were obtained with a clustered set of instrumentation that included the Millstone Hill incoherent scatter radar, the Boston University Mobile Ionospheric Observatory, and the HILAT and Defense Meteorological Satellite Program (DMSP) F6 and F7 satellites. In this paper the authors concentrate on data from the Millstone Hill incoherent scatter radar which was operated on selected evenings in a rapid azimuthal scan, centered on magnetic west. The mode was designed with the express purpose of measuring line-of-sight drift velocity and electron density as a function of latitude during events with large localized electric fields. On the evenings of April 20 and 21, 1985, during an intense magnetic storm, large ionospheric electric fields (E > 80 mV/m) were detected along the edge of the auroral oval with the Millstone Hill incoherent scatter radar. These constitute the first definitive incoherent scatter observations of this phenomenon. An L shell-aligned (zero order) deep trough in electron density was colocated with these large electric fields at L shells as low as L = 2.8. These data indicate that the trough develops much more quickly than present theories predict, at least near the F peak. They also report elevated ion and electron temperatures in the trough and conjecture that these may contribute to the rapid decay. They also show that the associated field-aligned currents are very weak. They also discuss the data set in light of competing theories for the production of large electric fields and for undulations of the edge of the diffuse aurora.
ISSN 01480227
Educational Use Research
Learning Resource Type Article
Publisher Date 1989-05-01
Publisher Place United States
Journal Journal of Geophysical Research
Volume Number 94
Issue Number A5


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