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.

injection is again r ather localized but it aeems to expand a little bit, because it is seen i n T horshavn aa well as in Kevo and Ivalo w h ic h are then more south reap.more east. 5. DISCUSSION A M D CONCLUSIONS. Searching for pronoimced auroral absorp tion events during globally very quiet conditions we found events in all local time sectors. Different types of events have be en found: SVA-events in the m o rning sector, events around midnight showing sharp injection onsets w i t h and without expansion, localized strong AA-events in the a fternoon seo- tor. All these events are somehow related to magnetic substorms. At a first glance all these events dont d iffer very m u c h fro m AA-events wh i ch have bee n found during more disturbed conditions, so that one geta the impression that the isolated substorm h as bee n sufficient to set in m otion all the principal physical processes leading to h i g h energy electron precipitation for such a stable quiet magnetosphere, too. The great advantage of the method use d here is that in most of the cases one is stable to define the signatures of the event in dependence on time quite easily and that the results are ver y clear. In order to decide the basic question w h e t he r the A A - su bstorm signatures depend on the state of the magnetosphere at the onset of the substorm, more detailed investigations a r e n eeded in future. Acknowledgements: This study n eeded a lot of data. The authors should like to thank the Wo rl d Data C enter A, Boulder, the World Data Center B, M o sc o w ( D r. A .Ya.Feldstein), D r . P .Stauning of the Danish Meteorological Insti tute, the SiblZMIR, I rk utsk-Norilsk and the Po l ar Geophysical Institute, Murmansk, for providing th e m w i t h these data. R E F E R E N C E S : Be r k l e y P.I., Dria ts k y V . M . , H e nriksen K . , Hultqvlst B . , Jelly D . H . , Shchuka T.I., Theander A,, Y l i n i e m i J . - P l a n e t . S p a c e Sci., 22, 255, 1974. B ew e r sdorff A., K r em s e r G., R i e dler W . , L e grand J.P. - Ark.Geopys., 5, 115, 1966. B ew e r sdorff A., K r e ms e r G,, Stadnes J., Trefall K . , Ullalund S. - J. A t mo s . Te r r . P h y s . , 30, 529, 1968. B r o w n R.R. - J.Geophys.Res., 69, 2315,1964. Collis P.N., Ko r t h A. - Planet.Space Sci., 31, 1373, 1983. Collis P . N . , K o r t h A. - J .A t m os . T e r r . P h y s , , 47, 327, 1985. Collis P . N . , Ko r t h A. - Planet.Spaoe Sci., 34, 293, 1986. Hargreaves J.K. - Proc.IEEE 57, 1348, 1969. K angas J . , Lukjcari L . , Tanskanen P., Trefall М., Stadnes J., K r e ms e r G. , Riedler W. - J , A tm o s .T e r r. P h ys . , 37, 1289, 1975. P ik k a rainen Т., K angas J.,Ranta H . , Ranta A., Maltseva N., Troitskaya V . , Afanasieva L. - J.Atmos.Terr.Ploys., 48,... 1986. I00