Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Universal time dependence of nighttime F region densities at high latitudes

Technical Report ·
OSTI ID:6130819
; ; ; ;
Coordinated EISCAT, Chatanika, and Millstone Hill incoherent-scatter radar observations have revealed that in the auroral zone, the nighttime F region densities vary substantially with the longitude of the observing site: EISCAT's densities are the largest and Millstone Hill's are the lowest. The nighttime F region densities measured by the individual radars are not uniform: the regions where the densities are maximum are the so-called blobs or patches that have been reported previously. The observations are consistent with the hypothesis that the nighttime densities are produced in significant amounts not by particle precipitation, but by solar EUV radiation and that they have been transported across the polar cap. The observed differences can be explained by the offset of the geographic and geomagnetic poles. A larger portion of the magnetospheric convection pattern is sunlit when EISCAT is in the midnight sector than when Chatanika is. In winter, when Millstone Hill is in the midnight sector, almost all the auroral oval is in darkness. This universal time effect, which was observed on all coordinated three-radar experiments (September 1981 to February 1982), is illustrated using two periods of coincident radar and satellite observations. These two periods were selected because they corresponded to relatively steady conditions. Dynamics Explorer (DE) measurements are used to aid in interpreting the radar observations.
Research Organization:
Southwest Research Inst., San Antonio, TX (USA)
OSTI ID:
6130819
Report Number(s):
AD-A-160574/0/XAB
Country of Publication:
United States
Language:
English

Similar Records

Universal time dependence of nighttime F region densities at high latitudes
Journal Article · Wed May 01 00:00:00 EDT 1985 · J. Geophys. Res.; (United States) · OSTI ID:5646986
Radar observations of structured plasma in high-latitude F region. Final report, 14 January 1980 - 31 March 1981
Technical Report · Sat Feb 28 23:00:00 EST 1981 · OSTI ID:5475787
Studies of the auroral-zone ionosphere using the MITHRAS data base. Fiscal years 1983-1985. Final report, October 1982-October 1985
Technical Report · Thu Jun 26 00:00:00 EDT 1986 · OSTI ID:6903290

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
640203 -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
CHARGE DENSITY
CHARGED-PARTICLE PRECIPITATION
CONVECTION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTROMAGNETIC RADIATION
ENERGY TRANSFER
EXTREME ULTRAVIOLET RADIATION
F REGION
GEOGRAPHICAL VARIATIONS
HEAT TRANSFER
IONOSPHERE
LATITUDE EFFECT
MASS TRANSFER
MEASURING INSTRUMENTS
PLANETARY IONOSPHERES
RADAR
RADIATIONS
RANGE FINDERS
SOLAR RADIATION
STELLAR RADIATION
ULTRAVIOLET RADIATION
VARIATIONS