Correlation of Ps6 pulsations of the geomagnetic field, variations in the total electron content, and the backscatter echo power during the large magnetic storm of September 24-25, 1998

Simultaneous observations of the variations in the geomagnetic field horizo ntal component (H), total electron content (TEC), and backscatter signal po wer have been analyzed. Experimental data have been obtained in the vicinit y of the Irkutsk geomagnetic meridian (Phi = 40.7 degrees, Lambda = 174.8 d egrees) during the large magnetic storm of September 24-25, 1998. It has be en indicated that the three factors mentioned above fluctuate with periods of Ps6 geomagnetic, pulsations between 0830 and 1130 UT. The oscillation sp ectra have common components, which are also present in the variations in t he geomagnetic field and TEC in the longitude sectors located 80 degrees an d 100 degrees westward and eastward of Irkutsk, respectively. The conclusio n has been drawn that the global excitation of the H and TEC fluctuations i n the Ps6 range on September 25, 1998, resulted from the increased substorm . activity in the nightside magnetosphere.