Joint two-dimensional observations of ground magnetic and ionospheric electric fields associated with auroral zone currents 1. Three-dimensional current flows associated with a substorm-intensified eastward electrojet
Two-dimensional distributions of ground magnetic and ionospheric electric fields in the evening sector auroral oval have been simultaneously observed by the Scandinavian Magnetometer Array and the Scandinavian Twin Auroral Radar Experiment (Stare) radars, respectively, on February 15, 1977. They were associated with varying, substorm-intensified, eastward electrojet current systems of the western, middle, and eastern segment of the eastward electrojet. We conclude that the substorm-intensified eastward electroject was a nearly pure Hall current driven by northward electric fields. The observed eastward increase of the current in the western segment of the electrojet was due to a gradual enhancement of the Hall conductivity. Here, the electrojet was fed by a broad sheet of net downward field-aligned current. During one period, the eastern-terminating part of the eastward electrojet diverged up the field lines in a rather local area because of a strong longitudinal decrease in the northward-directed electric field. On another occasion, it diverged northward within the ionosphere and joined the westward-flowing current because of a rotation of the northward electric field with increasing latitude through west- to southward. These two observed mechanisms of current divergence in the region where eastward and westward electrojects coexist may shed some new light on the controversy over the existence of upward field-aligned current flow in the Harang discontinuity.
- Research Organization:
- Institut fuer Geophysik der Universitaet Muenster, D-4400 Muenster, Federal Republic of Germany
- OSTI ID:
- 5336476
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 85:A5
- Country of Publication:
- United States
- Language:
- English
Similar Records
Rocket observations at the northern edge of the eastward electrojet
Estimation of ionospheric electric fields and currents from a regional magnetometer array
Related Subjects
GENERAL PHYSICS
ELECTROJETS
THREE-DIMENSIONAL CALCULATIONS
IONOSPHERE
AURORAL OVAL
CURRENT DENSITY
ELECTRIC FIELDS
GEOMAGNETIC FIELD
HARANG DISCONTINUITY
MAGNETIC BAYS
CURRENTS
EARTH ATMOSPHERE
ELECTRIC CURRENTS
MAGNETIC FIELDS
PLANETARY IONOSPHERES
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena