Электродинамические процессы в высоких широтах: материалы междунарордного симпозиума «Полярные геомагнитные явления», 25-31 мая 1986 г., Суздаль, СССР / Междунар. геодез. и геофиз. союз, Междунар. ассоц. геомагнетизма и аэрономии ; Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т ; [редкол.: О. М. Распопов (отв. ред.). и др.]. - Апатиты : Кольский филиал АН СССР, 1988.

Figure 2a. The same as Fig.1a Fig. 3a. The same as in Fig.1a on 17.8.1974. on 1.5.1975. precipitation juat after 14.00 UT w i t h a duration of about a n hour. Whereas this increase m a y still be related to a n injection at midnight i n connection wi t h the substorm, this seems to be impossible for the strong but rather localized ab s or p t io n increase at Xvalo (17.00 MLT) w h i c h is seen w i t h a small amplitude 130 k m a w a y in Sonadkyla.. B u t the next examples v/ill demonstrate similar cases i n the a f t e rn o o n sector. 4.2.2. M a y 1, 1975) 10.00-18.00 UT. F or this case the magnetic activity (AE i n Fig.3a) starts to inci'ease g r adually fro m v e r y low values already at 4.00 UT in c on n ection w i t h a southward excursion of the Bz-component but then it becomes quiet a n d starts to r^ise onoe more after 12.00 U T w h e n Bz turns southward again. The magnetic station in College n e a r magnetic midnight records disturbances a l re a d y fro m 10.30 UT, but this seems to be ve r y lo ca l ized, because Welen.n e a rb y sees substorm activity only from 13.00 UT (fig.3b). Man y other stations in the m o rn i n g sector as i.e. Churchill, Sitka, Great Whale see n o substorm activity. Preci pi t a ti o n starts in the early m o r n ing sector (Alaska chain - 2.5 MLT) at about 13.00 UT and then seems to move О towards n o o n (Churchill, Godthab) but always wi t h r ather low amplitudes. While no preci p i ta t i on w a s found i n the evening sector, the F i n n is h n e t work in the aft e rn o o n (17.00 MLT ) r ec o r ds the highest amplitudes and a localized increase ag a i n i n Xvalo (L»5.5). Perhaps two facts s h o ul d be mentioned: D uring this event there seems to occur some i njection of h i g h e nergy ions into the inner ma g n etosphere - Dst is b e c o mi n g a little bit negative for some hours (Fig.3a). Magnetic stations in n o r t he r n Europe show a smooth increase in H aft e r 13.00 UT for some ho u r s (Fig.3b). 94