Relative location of a powerful flare, the heliospheric current sheet and the Earth favourable for the onset of a strong geomagnetic storm

Problem of magnetic clouds propagation in regular-nonuniform internal heliosphere is discussed. High dependence of their retardation and consequently intensity of interplanetary and geomagnetic disturbances on mutual location of flares, heliospheric current sheet and the Earth is identified. Eight solar flares, four of which caused strong storms, and another four led to weak disturbances, all of them being in fair agreement with theoretical conclusions, are presented as examples