Diurnal and latitudinal variation of auroral zone ionospheric conductivity

Journal Article · Thu Jan 01 04:00:00 EST 1981 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA086iA01p00065· OSTI ID:6535483

Vickrey, J F; Vondrak, R R; Matthews, S J

The great spatial and temporal variability of auroral ionospheric conductivity significantly influences the ionospheric closure path for high-latitude, field-aligned currents. Becauce these closure paths can extend to low latitudes, changes in auroral zone conductivity can influence the global electric field distribution. In this paper, synoptic Chatanika radar observations of auroral zone conductivity that cover approx.62/sup 0/ to 68/sup 0/ geomagnetic latitude are presented. They are representative of quiet winter, active winter, and equinoctial conditions. During the daytime the solar contribution to the height-integrated conductivity is well represented by S/sub P,H/approx. =(5,10)cos/sup 1/2/(x), where x is the solar zenith angle. The nighttime, height-integrated Pedersen and Hall conductivities (S/sub P/ and S/sub H/) in the electron density trough are, at times, below our detection threshold of approx.0.5 mho. Following magnetic substorm onset, enhanced conductivity regions move southward and intensify. As the recovery phase begins, the conductivity pattern recedes northward and diminishes. The onset and cessation of precipitation associated with these events can be as abrupt as a few minutes. In one example the behavior of S/sub P/ and S/sub H/ are examined in the vicinity of the Harang discontinuity, which was quite sharp (< or approx. =30 min) in local time. At the Harang discontinuity on that day, the ratio of S/sub H/ to > or =/sub P/ decreased, indicating a softening of the precipitating energy distribution.

• Research Organization: Radio Physics Laboratory, SRI International, Menlo Park, California 94025
• OSTI ID: 6535483
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 86:A1; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAL OVAL
AURORAL ZONES
CHARGED-PARTICLE PRECIPITATION
DAILY VARIATIONS
EARTH ATMOSPHERE
ELECTRIC CONDUCTIVITY
ELECTRIC FIELDS
ELECTRICAL PROPERTIES
ELECTRON DENSITY
GEOGRAPHICAL VARIATIONS
HARANG DISCONTINUITY
IONOSPHERE
LATITUDE EFFECT
MAGNETIC BAYS
PHYSICAL PROPERTIES
PLANETARY IONOSPHERES
VARIATIONS