Исследование стационарной магнитосферной конвекции / В. А. Сергеев [и др.] ; Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Препр. ПГИ 86-05-47. - Апатиты : Кольский филиал АН СССР, 1986.

(more than 4— 5 hours). During the period from 12 UT on February 19 till 12 U T on February 20, 1978, three well-defined substorms are seen in AL index (Fig.1) and one more substorm started at 12.00 UT on Feb. 20. This determination is well supported by other ground substorm signatures, including midlatitude magnetic bays (MLB) and Pi2's. This information, shown also in Fig.1, is extracted from the mag netic data of world-wide station network, including rapid-run and induction magnetometer records from Fredericsburg, Tucson, Kanoya, Borok, and Wingst, well distributed in longitude. The data on Pi1B pulsation activity and information on auroras, when available, gave the same picture. In addition, we also show in Fig.1 the periods when the negative magnetic bays (HLB) were found at high- latitude stations Baker Lake, Beiss, Ny Alesund (all at ?4-75°Л ), when they are at the nightside. This information helps us to dis tinguish the periods when the auroral bulge and associated west ward AEJ expanded polewards from its nominal northernmost position at 70-72° during the disturbed periods under study (Section 4). Between the intervals, classified as clear substorms and shown by black space in the legend at the top of this Figure, there are 3 intervals (each more than 4- hours in duration) where no (or very weak signatures) substorm activity is noticed but auroral electrojet activity is still significant (both for westward and eastward AEJ*s ). Especially favourable SMC-like interval occured between 18 and 23 UT on Feb.19, 1978, where AE is sustained at the 300-400 nT level. It will be treated in more details in Sections 3,4. Quite a similar pattern is observed after 23 UT on November 23 throughout the whole day of November 24, 1981 (Fig.2). We em phasize here its first half, during which AE is again stable and rather intense ( ~ 400 nT). Unfortunately, the ground based infor mation available for this period is less complete. So, Pi2 identi fication was based on the data of two stations only (Memambetsu, Lovozero). IMF during these two periods had the desirable stability and southward orientation, although here are few spikes and иапу data gaps (especially for the Feb.1978 period, when IMF-8 made measure ments in the tailvard part of the magnetosheath). IMF B^. is nega tive during the first period and mainly positive during the second 15