Структура и динамика полярных токовых систем : материалы международного симпозиума «Полярные геомагнитные явления», 25-31 мая, Суздаль, СССР / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : [б. и.], 1988.

high-latitude auroras in the inner precipitation belt. However, the precipit ation is generally near the background level between the spikes and the contiguous belt, and it is therefore possible that the polar cap arcs have an origin different from those in the inner preoipitation belt. Response to the e -increase. At the time of the -increase Greenland was situated below the poleward extended low-energy electron precipitation belt (Fig.5). Therefore, it is possible to utilize the high time resolution in the photometer record to study the position of the dawnside poleward bound- ary'of the precipitation belt in the period following the increase. It has already been demonstrated that the 350 R contour in Pig.5 follows the course of the polar cap boundary during the quiet interval 00 to 05 UT. Between aproximately 04 and ОбUT the contour is too far north to be observed from Godhavn, but at 06 UT it is abruptly shifted to a position south of the station. The course of the 800 R contour indicates a gradual southward shift of the emission beginning shortly after the disturbance at 0510 UT and contin uing till after 06 UT. < In Pig.7 we present a stackes plot of photometer sweeps taken during the interval 0431-0635 UT. The main maximum on the southern sky indicates the position of the auroral oval. Other maxima are related to sporadic occurence of visual or subvisual forms. Notioe the difference in appearance between sweeps before and after 06 UT. Sporadic intensity maxima are abundant before, but absent after this hour. Thus, the figure locates the disappearance at II DISCRETE AURORA (PHOTOMETER) 300 km 0 DISCRETE AURORA (ALL-SKY CAMERAI 110 km 1 DIFFUSE AURORA (ALL-SKY CAMERAI 5 PATCHY AURORA (ALL-SKY CAMERAI e h o w l S ei n t a n 2 t y° S t6300Wr S S i B e i o n of the-position of observed 6300 A inten- anowing ini-ouaj. j ___ __ nltv maxima. the nosition in the егеотаг- Pig. 8. Variation with Univergal Time along the geomagnetic meridian through Godhavn on Hov.29,1984 every 4 minutes between 0431 and 0635 UT. sity maxima, the position in the geomag netic meridian through Godhavn-Sondre Stromfjord of visual auroras and position of precipitation boundaries observed by DMSP-satellltes in the dawn sector. Also shown are 4 consecutive observations with Incoherent Scatter Radar at Soundre Strom- fjord of position of convection reversal (bars).