Electrostatic potential in the auroral ionosphere derived from Chatanika radar observations

Journal Article · Wed Sep 01 04:00:00 EDT 1982 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA087iA09p07513· OSTI ID:6573971

Foster, J C; Banks, P M; Doupnik, J R

A technique is described for determining the latitudinal variation of the electrostatic potential associated with the ionospheric convection electric fields. Using the north-south electric field component derived from radar convection velocity experiments, the integral of Exd1 is taken northward along the magnetic meridian, starting at low latitudes. The radar data consiste of up to 40 independent measurements of plasma convection spanning 15/sup 0/ of invariant latitude centered on Chatanika, Alaska (65 /sup 0/..lambda..), with half-hour temporal resolution. It has been found that (1) the electric field contributions to the potential at and below 60 /sup 0/..lambda.. are small under most circumstances and (2) the latitudinal variation of the potential is smooth and regular, permitting the potentials to be contoured across local time. It is found from the experiments that the potential often varies uniformly over 10 /sup 0/ latitude at dawn and dusk. Electric fields of 50 mV/m are common. It is also noted that the latitude of the greatest negative potential in the premidnight sector coincides with the Harang discontinuity in ionspheric currents. The potentials calculated from the measured plasma drifts exhibit a regular local time variation. Equipotential contours derived from the latitude-local time potential field obtained with the long-duration radar experiments, while not providing a snapshot of the instantaneous pattern, elucidate the large-scale diurnal variation of the electrostatic potential at auroral latitudes. From such contours it is found that a two-cell convection pattern with varying degrees of asymmetry is consistently present at auroral latitudes, that a cross-polar cap potential drop of 70--120 kV is present in moderately disturbed conditions, and that substorms perturb the potential pattern at all local times.

• Research Organization: Center for Atmospheric and Space Sciences, Utah State University, Logan, Utah 84322
• OSTI ID: 6573971
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 87:A9; 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
AURORAL ZONES
DISTRIBUTION
EARTH ATMOSPHERE
ELECTRIC FIELDS
ELECTRIC POTENTIAL
ELECTROSTATICS
GEOGRAPHICAL VARIATIONS
IONOSPHERE
LATITUDE EFFECT
MEASURING INSTRUMENTS
PLANETARY IONOSPHERES
RADAR
RANGE FINDERS
SPATIAL DISTRIBUTION
VARIATIONS