Global ionospheric current distributions during substorms

Journal Article · Thu Mar 01 04:00:00 EST 1984 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA089iA03p01613· OSTI ID:6468487

Ahn, B; Kamide, Y; Akasofu, S

The growth and decay of global ionospheric currents during magnetospheric substorms on March 17, 18, and 19, 1978 are examined on the basis of magnetic records from the six IMS meridian chains of observatories and others (the total number being 71). The computer code developed by Kamide et al. (1981) and the conductivity model developed by Ahn et al. (1983) are used. Several substorms centered around 1000-1200 UT are chosen in this presentation, since the simultaneous all-sky and riometer records are essential in timing the substorm epochs. Several global feautes that are common to most substorms during the three-day interval include the following: (1) During a quiet period, currents are often present in the cusp and/or polar cap regions. The cusp current consists of a pair of east-west currents and the polar cap current consists of several vortices. (2) When the interplanetary magnetic field (IMF) B/sub z/ component is positive, but decreases in magnitude, a well-defined westward electrojet develops in the midnight sector. However, this development is not evident in the AE index. (3) A gradual, but distinct growth (often followed by a rapid and large increase) in the AE index is indentified as the intensification of a weaksubstorm current system, which was mentioned in (2), accompanied by typical auroral substorm features, including riometer absorption. (4) The subsequent sharp increase of the AE index arises primarily from a deep intrusion of the westward electrojet into the pre-midnight sector and its equatorward shift. (5) The overall increase of the global current can be significantly differnt fromm what a sharp increase of the AE index indicates. (6) During the recovery phase, the intruded westward electrojet recedes towards the dawn sector.

• Research Organization: Geophysical Institute, University of Alaska, Fairbanks, Alaska 99701
• OSTI ID: 6468487
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 89:A3; 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
CURRENTS
EARTH ATMOSPHERE
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
INTERPLANETARY MAGNETIC FIELDS
IONOSPHERE
MAGNETIC BAYS
MAGNETIC FIELDS
PHYSICAL PROPERTIES
PLANETARY IONOSPHERES
POLAR CUSP