Аскаплоты советских станций за 1978 год : (оперативно-информационный материал) / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : Кольский филиал АН СССР, 1981.

II absence and. even at absolutely quiet periods homogeneous axes (HA) and bands (HB) with brightness gaining sometimes 2 balls (these are not the balls of activity but balls of brightness, according to International Classification) may be observed along the compressed oval. At the dayside weak radiant arcs are usually seen. A weak substorm brings brightness increasing, appearance of curves, i.e. transition of arcs into bands and radiant structure developping. Strong substorm із characterized by apparent breakup, i.e. by quick motions of aurorae, collapse of forms, coronae and pulsating aurorae appearance. Thus, the aurox'ae activity magnitudes Table used at ascaplotting is connected with substorm development pecularitlee and characterizes to some extend its intensity. The example of aecaplota is presented in Fig.2. The numerals I-XV show various possible situations. The camera didn't operate until 1 3 . 3 OUT at the given example. The observations began in ' 13 * 3 0 U T » aurorae are absent, in the north and in the zenith the cloudiness is with rents (I). During the next half-an-hour interval (II) aurorae are absent either, complete cloudiness is in the north and in the zenith, in the south - cloudiness with rents; III and IV correspond to time intervals with complete cloudi ness covering all the sky} V — cloudiness with rents in the south and in the zenith, in the north - no clouds. Aurorae in the north appeared at 16UT (VI), in the zenith- no clouds, in the south - cloudiness with rents. VII - the sky is cloudless, aurorae are observed in the north and. in the zenith. VIII - the sky is clear, aurorae only in the north, local geomagnetic night. IX - aurorae shifted to the zenith once more and their activity gained 2 balls, in the south - cloudless. X - aurorae spread all over the aky, activity in the zenith equals to 3 balls. XI - aurorae in the north and in the zenith, activity of 3 ball, south - cloudless.no aurorae. XII - no aurorae ob served in the north, probably, because of cloudiness with rents, activity in the ze nith reduced to 2 balls. XIII - aurorae of not more than 1 ball are observed in the north and in the zenith, the south is cloudless. XIV - the sky is cloudless,no auro rae, moon lighting appearance. XV — the similar situation, but askafilm due to tech nical cause (bad developping of this part of the film, breaks in automatics work) found out to be of bad quality. The described example presents practically all situa tions one may come across in aacaplots. Auroral index PA. The index of aurorae activity, calculated with the help of ascaplots was suggested in / 13 /. It equals to PA = N К (Ф Л ), where И- the number of blacked squares in time interval, and К- coefficient, depending on the latitude and longitude. The connection between N and auroral magnetic index M for midnight hours was determined in /13/ from ascaplots of 35 stations during luY and I(JS. Using the same data the dependence of К coefficient on the latitude were obtained for two longitudinal intervals. This allows to use the data of the stations located at diffe rent latitudes for the value of M. So that index К was calculated for midnight sta tions, PA index is eetimated only for 4-hours interval in the region of the local geomagnetic night. M scales are chosen so that the corresponding values of PA index were linearly proportional to the energy of auroral electrons of the aurorae oval /13/» ThJ-s allows to make any arithmetic operation with PA index, such as averaging without lost of physical content. Table 2 includes PA values for each day of 1978. Taking one station,PA may be determined only for 4 -hours interval that may not coinsid,e with auroral activity maximum. In this relation Table 2 presents PA values obtained by indices averaging of all stations operated at that day. The number of the stations operated is given in brackets at each index, the data of these stations entered those averaged for