Modeling the Connection of the Global Ionospheric Electric Fields to the Solar Winds
AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE WEATHER CENTER OF EXCELLENCE
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A global ionospheric electrostatic potential model, which we refer to as Nopper-Carovillano N-C, can be linked with a magnetospheric potential model. The latter model, which we refer to as Hill-Siscoe-Ober H-S-O, computes a transpolar potential phipcH-S-O based on solar wind parameters and region-1 field-aligned currents FAC from the magnetosheath to the ionosphere. The polar ionospheric conductance required by H-S-O is defined by the N-C model. In this way, the transpolar potential and the associated FAC are the same in both models. A distribution of region-1 FAC in the N-C model predicts a two-cell convection pallem which is in reasonable agreement with plasma drifts measured by DMSP Defense Meteorological Satellite Program satellites. The H-S-O model, as modified by N-C, is compared with the Weimer potential model and with the transpolar potentials observed by DMSP satellites during the 6-7 April 2000 magnetic storm. Good agreement is found in both cases. The region-2 J2 current is estimated from the Siscoe S-RC ring-current circuit model which is driven by phipcH-S-O. The resistor values in S-RC, as determined by N-C, when combined with the global potential solution, make it possible to estimate the time profile of the equatorial penetration electric field during the storms main phase. With the values obtained, shielding occurs within 1 hour of onset. Equatorial plasma bubbles EPBs are seen some hours after the initial increase of phipc and are qualitatively consistent with the equatorial penetration electric field calculated by the combined model.
- Atmospheric Physics
- Electricity and Magnetism