Publikationsdatum:
2014-04-05
Beschreibung:
In order to explain the observed ionospheric TEC variations before strong earthquakes, we have developed a comprehensive model for the lithosphere-atmosphere-ionosphere (LAI) coupling. In our previous model, the background magnetic field was assumed to be perpendicular to the horizontal plane. In the present paper, we improve the calculation of currents in the atmosphere by solving the current density J directly from the current continuity equation ∇ • J = 0 . The currents in the atmosphere can be solved for any arbitrary angle of magnetic field, i.e., any magnetic latitude. In addition, a large ratio (~10) of Hall to Pedersen conductivities is used to generate a large Hall electric field. The effects of atmospheric currents and electric fields on the ionosphere with lithosphere current source located at magnetic latitude 7.5°, 15°, 22.5° and 30° are obtained. For upward (downward) atmospheric currents flowing into the ionosphere, the simulation results show that the westward (eastward) electric fields dominate. At magnetic latitude 7.5° or 15°, the upward (downward) current causes the increase (decrease) of TEC near the source region, while the upward (downward) current causes the decrease (increase) of TEC at magnetic latitude 22.5° or 30°. The dynamo current density required to generate the same amount of TEC variation in the improved model is found to be smaller by a factor of 30 as compared to that obtained in our earlier paper. We also calculate the ionosphere dynamics with imposed zonal westward and eastward electric field based on SAMI3 code. In the nighttime ionosphere, it is found that the westward electric field may trigger two plasma bubbles on the two sides of the imposed electric field region, while a single plasma bubble is formed just above the imposed eastward electric field region.
Print ISSN:
0148-0227
Thema:
Geologie und Paläontologie
,
Physik
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