An Approach to Model Earth Conductivity Structures with Lateral Changes for Calculating Induced Currents and Geoelectric Fields during Geomagnetic Disturbances

Figure 6

Electric field at the Earth’s surface. Solid lines represent results from 2D FEM and symbols represent results from 3D FEM. (a) Real part and (b) imaginary part. Again the results agree very well with each other. Close to the horizontal interface of the two conductivity structures, the electric field increases at the resistive side whereas decreases at the conductive side. This performance is similar to the coast effect. The physical explanation is that the discontinuous conductivity will lead to an abrupt change of the electric field to guarantee continuity of the induced currents.

(a)

(b)