Координированные наблюдения авроральных явлений 1-2 декабря и 11-12 декабря 1977 г. на Кольском полуострове и в Финляндии / С. А. Черноус, Н. И. Федорова, Г. А. Логинов и др. ; Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Препр. ПГИ-79-3. - Апатиты : [б. и.], 1979.

As it conceives to us the morning red aurora of Dec. 1/2 depended on plasma flow from the day side rather than from the night. If the last case precipitation energy spec trum would be harder in the morning sector relatively to night. The hardening of morning spectrum is confirmed by the presence of auroral pulsations in the recovery phase of substorm being caused by hard electron precipitation ( E ^ 3 0 keV) [ 10 ] as it is mentioned above. This hardening is because the drift time of soft electrons ( E ^ 1 keV) from the night sector to the morning amounts to many hours that is more or at any case comparable with electron life time and consequently soft electrons will disappear before reaching the morning sector. Conclusions. The analysis of abnormal morning events on Dec, 1/2 1977 bring us to an assumption that the red A-type auroras in the morning sector are attributed to the dayside oval auroras. Many authors [22-24-J identify the dayside auroras with the dayside polar cusp auroras caused by di rect penetration of the magnetоsheath particles to iono spheric heights. However there is another opinion viz. the dayside polar cusp auroras are disposed poleward of the dayside oval and what is more there is some separation perhaps between two precipitation regions [ 25 - 2 ?]. We hold the first theory and such facts confirm our con clusions as it appears to us. 1. Sharp softening of precipitating electron energies in s the period of red aurora observations. 2. Similarity of spectral characteristics of red auroras observed on Dec. 1/2 1977 and characteristics of the day side polar cusp auroras under disturbed conditions [11,12, 25 ]. 3. Presence of rayed forms with lifetime about several minu tes. Just the same structures are typical for the dayside auroras which are associated with the dayside polar cusp [ 2 ]. There may be such reasons against the hypothesis of the cusp registration in our observations. 1. The region occupied by projection of the cusp on iono spheric heights is attributed to higher latitudes [22,