The role of the equatorial electrojet in the evening ionosphere

Journal Article · Sat Feb 01 04:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA02227· OSTI ID:5361916

Haerendel, G; Eccles, J V ^[1]

---

1. Max-Planck-Inst. fuer extraterrestriche Physik, Garching (West Germany)

This paper focuses on the role of the equatorial E region in the electrodynamics of the evening ionosphere. The influence and reaction of the electrojet current on the equatorial ionosphere at sunset is investigated using a field line integrated, one-dimensional, electrodynamic model. The one-dimensional, time-varying model predicts the divergence of the horizontal current of the equatorial electrojet for a given time variation of the horizontal electric field. The negative divergence of the horizontal current during the evening hours provides a net upward current out of the equatorial E region into the integrated ionosphere of higher equatorial altitudes. This upward current affects the vertical electric field magnitudes and subsequent horizontal plasma drifts of the overlying ionosphere. The model allows for chemical recombination and dynamic redistribution of ionization within the electrojet region under the assumption that the profile of the ionization density along a field lie is proportional to the chemical equilibrium profile. The eastward horizontal electric field and the net upward current during the 2 hours after sunset combine to lift the ionization out of the E region resulting in ionization densities less than the equilibrium values. As the ionization densities (conductivities) are reduced, the electrodynamics of the equatorial ionosphere is altered. This model of the equatorial electrojet current divergence can be used as a lower boundary to global, two-dimensional models of the equatorial electric fields. Finally, it is proposed that the equatorial electrojet current near sunset has a significant role in the determination of the postsunset enhancement of the horizontal electric field.

• OSTI ID: 5361916
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A2; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CURRENTS
E REGION
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTRODYNAMICS
ELECTROJETS
F REGION
GEOMAGNETIC EQUATOR
IONIZATION
IONOSPHERE
MATHEMATICAL MODELS
PLANETARY IONOSPHERES
PLASMA DRIFT
RECOMBINATION
TIME DEPENDENCE