Convection electric fields and ionospheric currents derived from model field-aligned currents at high latitudes
Computer simulations of convection electric fields and ionospheric currents driven by high-latitude field-aligned currents (FAC) have been conducted with an emphasis on field-aligned currents in the dayside high-latitude region. The particle-induced conductivity is based upon average particle precipitation fluxes observed by Atmospheric Explorer. In order to examine conclusions drawn from satellite observations, the field-aligned currents in the region of the dayside cusp are modeled in two ways. First, the cusp FAC are given as distinct currents poleward of the auroral oval field-aligned currents. Their location and direction of current are determined by the B/sub y/ component of the interplanetary magnetic field. Second, the cusp FAC are given as an extension of the morning (or evening) region 1 current across the noon meridian and into the polar region for IMF B/sub y/ <0 (or B/sub y/ >0). The second, or overlapping, representation of FAC sheets near noon yields ionospheric currents that match the DPY current system better than the distinct cusp FAC model. The calculated convection electric fields do not show a drawing together of electric field equipotentials near noon to form a 'throat' of rapid convection. Variations of the model might yield a throatlike convection pattern on one side of noon but not both sides. The model results give a westward electrojet on the poleward edge of the evening region 1 as a natural part of the global ionospheric current system.
- Research Organization:
- Air Force Geophysics Laboratory, Hanscom AFB, Bedford, Massachusetts 01731
- OSTI ID:
- 6079564
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 88:A1
- Country of Publication:
- United States
- Language:
- English
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