A two-layer model for the geomagnetic crochet

During a solar flare ionospheric current flows both in the E- and the D-regions and the flare time current can be considered as the super-position of two current systems psisup(E) and psisup(D). Equations are established for these current functions which are coupled with each other because of the transient nature of the phenomena. Solutions for psisup(E) and psisup(D) are obtained in terms of the time dependence of the ionospheric conductivity functions during a flare. It is demonstrated that some of the morphological characteristics of the flare time current system can be explained in terms of this two layer model. (author)