Radar and optical measurements of ionospheric processes associated with intense subauroral electric fields

Journal Article · Mon May 01 04:00:00 EDT 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA05p05350· OSTI ID:5831439

Providakes, J F; Kelley, M C; Swartz, W E ^[1]; Mendillo, M ^[2]; Holt, J M ^[3]

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1. Cornell Univ., Ithaca, NY (USA)
2. Boston Univ., MA (USA)
3. Massachusetts Institute of Technology, Westford (USA)

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.

• OSTI ID: 5831439
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 94:A5; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
AURORAL OVAL
CURRENTS
E REGION
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTRON DENSITY
ELECTRON TEMPERATURE
F REGION
GEOGRAPHICAL VARIATIONS
ION TEMPERATURE
IONOSPHERE
LATITUDE EFFECT
MAGNETIC STORMS
MEASURING INSTRUMENTS
PLANETARY IONOSPHERES
RADAR
RANGE FINDERS
SATELLITES
TEMPERATURE GRADIENTS
VARIATIONS