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.

The December 27. 1984 c a s e . Figure 2a shows simultaneous multi-channel observations of day- an d night-side auroras. A stable, quiet cusp arc was located to the no r t h of Longyearbyen for several hours around magnetic noon (0830 UT). Be t w e e n 1130 and 1210 U T the luminosity moved rapidly towards the southern horizon. Associated w i t h this auroral movement the H-component m a g netic field (Ny Aleeund) went negative. A southward expansion of the m i d night aurora occurred i n the same period, ind icating a large radial expansion, of the аигогчі oval, following a southward turning of the IMF vector (left panel). The I M P observations were recorded by the AMPTE-UKS satellite located close to tfre b o w shock in the dawn sector. At about 1210 UT a major subptcrra intensification occurred in the Alaska sector. The H-cowponent at Arctic Village, shown in the right panel of I'ig.2a, is a representative of the night- side w e stward electrojet ap observer! Ъу the Alaska chain during the substorm (Pig. 2b). B e t w e e n 1300 a nd 1330 UT (eppr.16 MLT) northward and southward turnings of the IM P are observed to be associated w i t h poleward and subsequent equat,от- ward movements of a n east-west aligned auroral arc. The spacecraft crossed the bow-shock at 1304 (inbound) and at 1319 UT (outbound). A perturbation at 1234 U T is due to a ba r i u m release from a companion satellite (AUPTE IRM). W h e n comparing the quiet, midday aurora (cf.Pig.2a appr. 1030 UT) w i t h the afternoon polar cap n?c (1310-1330 UT), we notice a significant d i f f e r ence in the spectral ratio 1(630.о nm)/I(557.7 nm). The latter one shows * stronger green line emission an d e lower value of this ratio than the midday aurora. M O P али BRM C P Y IHK AVI FYU T L K Figure 2b. H-component magnetic redordinga for D e c . 27,1984 from the Alaska-Canada meridian chain of stations, ranging from 62° to 79° geom,l*t„, Я4 ML T correeoinds to ~ 11 UT. 362 • v V w * V - * •.A- Ѳ6 J li* 2 4 M U '•^v. f -J----- S - is 3i 120