Авроральные явления 70-I : материалы наблюдений Полярного геофизического института за первое полугодие 1970 г. / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т ; [отв. ред. Б. Е. Брюнелли]. - Апатиты : Кольский филиал АН СССР, 1973.

. ,»«nua r.r 1-2 disturbance (Fig.21-23, 25) contains three interesting points. 1'Ьхв aaeturbance start the transition from the very quiet period to the enhanced one ana consequently illustrates the ionosphere changing from the rear observed i>»Q*viour of f 72 with a night minimum to the usual one, with the might maximum, tne evening polar aurora was accompanied by the positive bay; the arc and a current center were situated to the north from the station and no Measurable ab- eorption was observed. The nignt substorm was accompanied by the movement of the arc to tne equator during the pre-breakup phase, fast motion of the north boundary eauatorwards during the expansive phase and by the contraction of the background to the arc during the recovery phase. 2. During the night January 2-3 (Fig.26,27) magnetic etoxm was still in pro gress. In tne evening sector disturbance was developed as a prolonged positive bay; absorption increase take place only with small £ Z, i.e. equivalent current near the station zenith. Following negative disturbance contained some bursts, optical effects and absorption increase also have been observed mainly at the time of the zenitn location of the equivalent current. 3. January 2 0 disturbance (Tig.26) has a form of a isolated sharp negative »a.y according by intense variation of the declination and small 82. Large absorp tion was observed presumably during the growth phase of the bay development. Some dasconsistency is observed between the absorption behaviour measured by the глотеter and ionosonde owing to the difference in the antennae orientation. 4. Disturbance of January 30-31 (Fig.29,30) is characterised by rather strong optical effects accompanied by the appreciable ionospheric absorption whereas magnetic field variations were relatively very weak. Two sometimes decreasing arcs were observed at the enhanced background with an abrupt poleside boundary and smooth equatorial one. In the northen part of the sky two bright bursts with a semicorona were observed at 2249-2253 and 2 3 0 5 - 2 3 0 8 ; one of them coincided with unusual late transition of the B—component through the zero level. Characteristic poleward displacement of the auroral forms was not observed but rather equatorward shift of the forms with a highest brightness was taking place. 5. The night from February 2 to 3 (Fig.31-34) was characterised by a sequence of substorms. It is characteristic for the first one (1800-1900) that aurora and absorption activity were not accompanied by a magnetic disturbances. This effect may be ascribed to the insensibility of the magnetic field to the particles precipitation near the time (1800UT of February 2) of the positive to negative lieturbance transition. Another distinctive feature of this substorm, as well as the next one started 2 2 0 0 - 2 2 0 5 is an absence of the measurable equatorward shift luring the pre-break-up phase. Observed peaks of the aurora brightness during all this sequence of the substorms are not attributed to the background luminosity enhancements, but to the appearance of the bright forms near the zenith. fa. February 17-1b night (Fig.35) was marked by rather strong enhancement with one positive and two negative bays. Among the similarity of the auroral, magnetic ana ionospheric activity rates during all substorms magnetic variation maximums were delayed. Positive bay was accompanied by the appearance of the sporadic layers with the maximal frequency up to 4 MHz, the negative ones - by the blackouts. 7. February 24 disturbance (Fig.36,37) have a form of isolated positive bay with the transit to the small negative one. The rise of H-component coincides with some increase of the absorption, substantional fall of fQF2 and the appearance of the sporadic layer. After the transition of magnetic field variation through the maximum the auroras appeared. Transition of the equivalent current through the zenith was marked by an steep burst of an absorption and blackout. During the positive—to—negative bay transition enhancement of the aurora was observed: increase of the arc brightness, new arc appearance with the following poleward shifting »nri attenuation of tbe both of them.