Geomagnetic field as a sensor of the large-scale structure of the interplanetary medium

Application of various geomagnetic data to restoration of the heliospheric current sheet configuration in the past is discussed. Technique for such a restoration is proposed based on analysis of information on the interplanetary magnetic field polarity inferred from diurnal variation of the geomagnetic field in polar regions outer solar corona pictures resulting from solar eclipse observations are concerned with the heliospheric sheet configuration. So, days of past solar eclipses must serve as a kind of reference points in the course of the heliospheric sheet reconstruction.