Neutral winds and thermosphere/ionosphere coupling and energetics during the geomagnetic disturbances of March 6-10, 1989
- Massachusetts Inst. of Tech., Westford (USA)
Observations of electron density made using the fully steerable 46-m-diameter antenna at Millstone Hill have been used to derive the peak electron density (NmF2) and the peak height of the F2 region (hmF2) as a function of latitude during the March 6-10, 1989, period. This period was characterized by varying levels of geomagnetic activity, with a magnetic storm commencing near 1,800 UT on March 8. The radar data set presented for this period provides a detailed example of the mid-latitude ionospheric response to geomagnetic disturbances. The derived hmF2 values are combined with measurements of electric field-induced ion drifts and the MSIS-86 model to estimate the meridional neutral winds at thermospheric heights over the geodetic latitude range 30{degree} to 56 N. Strong postmidnight surges in the neutral wind were observed on March 7, 9, and 10 which reached well equatorward of Millstone Hill. The nighttime electron density trough was above Millstone Hill during the disturbances and hmF2 exceeded 500 km in the trough on March 7 and 9. A dusk enhancement in NmF2 followed the magnetic storm commencement on March 8. This is associated with a large increase in westward ion velocity due to the equatorward penetration of magnetospheric electric fields. Large daytime decreases in NmF2, apparently due to a neutral composition disturbance zone, were observed on March 9 and 10, with a sharp gradient on March 9, and a stronger equatorward penetration of the NmF2 decreases on March 10. The Joule heating as a function of latitude is estimated for March 7 and March 9 from calculations of height-integrated Pedersen conductivity and incoherent scatter electric field measurements. In spite of considerably more Joule heating input at high latitudes on March 9, the postmidnight surge is stronger on March 7. This is explained by a combination of Coriolis and ion drag effects.
- OSTI ID:
- 6159530
- Journal Information:
- Journal of Geophysical Research; (United States), Vol. 95:A12; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
F2 LAYER
ELECTRON DENSITY
HEIGHT
EARTH MAGNETOSPHERE
ELECTRIC CONDUCTIVITY
ELECTRIC FIELDS
ION DRIFT
IONOSPHERE
IONOSPHERIC EFFECTS
JOULE HEATING
LATITUDE EFFECT
MAGNETIC STORMS
RADAR
THERMOSPHERE
VARIATIONS
WIND
DIMENSIONS
EARTH ATMOSPHERE
ELECTRIC HEATING
ELECTRICAL PROPERTIES
F REGION
GEOGRAPHICAL VARIATIONS
HEATING
MEASURING INSTRUMENTS
PHYSICAL PROPERTIES
PLANETARY IONOSPHERES
PLASMA HEATING
RANGE FINDERS
RESISTANCE HEATING
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)