Chatanika radar observations of the latitudinal distributions of auroral zone electric fields, conductivities, and currents

Journal Article · Sat Apr 01 04:00:00 EST 1978 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA083iA04p01463· OSTI ID:7087885

Horwitz, J L; Doupnik, J R; Banks, P M

The latitudinal distributions of convection electric fields, height-integrated Hall (..sigma../sub H/) and Pedersen (..sigma../sub P/) conductivities, and horizontal currents in the auroral ionosphere have been measured with the Chatanika incoherent scatter radar for the range of invariant latitudes 63/sup 0/--68/sup 0/. Approximately 60 hours of data were obtained for three geomagnetically disturbed days: January 18, May 16, and May 17, 1974. During this observation period the general electric field properties, as functions of latitude and time, were as follows: (1) Strong electric fields in the range 50--100 mV/m were typically directed northward in the afternoon-evening sector and southward in the morning sector; (2) the electric field strength tended to increase with increasing latitude, with latitudinal scale lengths of 1/sup 0/--3/sup 0/. (3) In several instances a reversal of the electric field direction occurred at the highest latitudes probed, corresponding to antisunward plasma convection near the boundary of the polar cap. (4) The Harang discontinuity in the electric field was seen in the midnight sector (2200--0100 MLT) as a complex rotation of the electric field vector counterclockwise from northward through westward to southward, beginning at the highest latitudes, as the radar moved in local time through the Harang discontinuity.Association of the electric fields with the conductivities showed that (5) those early evening sector electric fields which were embedded within diffuse auroral precipitation tended to have less latitudinal and temporal structure than did midnight-morning sector electric fields embedded within active and highly structured precipitation and that (6) the local time transition between the diffuse precipitation-conductivity zone in the evening sector and the harder, active precipitation-conductivity zone in the midnight-morning sector coincided with the Harang discontinuity in the electric field.

• Research Organization: Magnetospheric Physics Branch/ES53, Space Sciences Laboratory, Marshall Space Flight Center, Huntsville, Alabama 35812
• OSTI ID: 7087885
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 83:A4; 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 OVAL
AURORAL ZONES
CURRENTS
EARTH ATMOSPHERE
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTRICAL PROPERTIES
GEOGRAPHICAL VARIATIONS
HARANG DISCONTINUITY
INCOHERENT SCATTERING
IONOSPHERE
LATITUDE EFFECT
MEASURING INSTRUMENTS
PHYSICAL PROPERTIES
RADAR
RANGE FINDERS
SCATTERING
VARIATIONS