On the relationship between dynamics of the polar thermosphere and morphology of the aurora: Global-scale observations from dynamics explorers 1 and 2

Journal Article · Fri Apr 01 00:00:00 EST 1988 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA093iA04p02675· OSTI ID:6092118

Killeen, T L; Ponthieu, J J; Hays, P B; Carignan, G R ^[1]; Craven, J D; Frank, L A ^[2]; Spencer, N W; Brace, L H ^[3]; Heelis, R A ^[4]; Roble, R G ^[5]

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1. Univ. of Michigan, Ann Arbor (United States)
2. Univ. of Iowa, Iowa City (United States)
3. Goddard Space Flight Center, Greenbelt, MD (United States)
4. Univ. of Texas, Dallas (United States)
5. National Center for Atmospheric Research, Boulder, CO (United States)

Simultaneous measurements of global-scale auroral luminosity distributions and neutral winds over the northern (winter) polar cap have been obtained using instrumentation on the Dynamics Explorers 1 and 2 spacecraft. Several examples of these simultaneous measurements are presented to illustrate the relationship between the circulation of neutral air in the high-latitude F region and the spatial distribution of the aurora. The initial study of these data indicates (1) that a definite correlation exists between boundaries in the neutral wind field and the location of the auroral oval with large-scale features of the neutral circulation tracking the substorm-dependent expansion and contraction of the auroral oval; (2) that the influence of ion drag from sunward convecting ions can extend to latitudes much lower than those normally associated with the auroral oval; (3) that the sunward neutral flow associated with the auroral oval in the dusk sector is in general, more pronounced than that associated with the dawn sector and that this asymmetry is ascribed to the different effect of the Coriolis force in the two sectors; (4) that the flow patterns for neutrals and ions within the geomagnetic polar cap are generally asymmetric with respect to the noon-midnight meridian, an effect considered to be controlled by the orientation of the interplanetary magnetic field; (5) that the region of the polar cusp and the apparent midday gap, or reduction in luminosities observed in the VUV wavelength auroral images near local noon, is closely associated with a large, antisunward surge in the neutral wind; and (6) that the morphology of the ion drag force in the polar regions is considerably more complex, even for very quiet geomagnetic conditions, than that computed by the National Center for Atmospheric Research thermospheric general circulation model for the steady state.

• OSTI ID: 6092118
• Journal Information: Journal of Geophysical Research; (United States), Vol. 93:A4; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
MORPHOLOGY
THERMOSPHERE
DYNAMICS
ASYMMETRY
AURORAL OVAL
CHEMICAL COMPOSITION
CORRELATIONS
EXPLORER SATELLITES
F REGION
FABRY-PEROT INTERFEROMETER
INTERPLANETARY MAGNETIC FIELDS
ION DENSITY
ION DRIFT
LUMINOSITY
POLAR CUSP
POLAR REGIONS
SPATIAL DISTRIBUTION
WIND
DISTRIBUTION
EARTH ATMOSPHERE
INTERFEROMETERS
IONOSPHERE
MAGNETIC FIELDS
MEASURING INSTRUMENTS
MECHANICS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLANETARY IONOSPHERES
SATELLITES
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)