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.

horizontal component of the magnetic field from middle latitudes (from middle latitude Magnetic Observatory Panagjuriate)j c) the solar wo n d veloci- p ty V s_w , denoity n sw and the parameter nVg.^; d) the components of the IMP (taken from Solar G.Data, 10,1985, 494 II) given as a strong factor rather Dst than V g w . Por the interval 21-23.09.1984 the regression analysis gives: Л[. „ = - а т ІІ-0.ЩТІ!)І-0ШН+0.53Ѵ+0.0Ьп+Ѳ.ЯпѴі+0МХ#*ЩАН)г*ШѴ*+ІІ.в2п,*0.Ц(ііІ/1) 2 ( 1 ) AH.s=--0.70])st-0.10Allst-0.01AH+Om+Q№Vt+Omti+(J03i])tf+OJ‘i(M)t+0.72V2-0.01n**0.2r(liV2) Z It is characteristic for this period that Vgyf varies from 400 to 800 km/sec and Dst accepts values from 0 to -54» i.e. only negative ones. Such an analysis has been made for a quiet period from 3.10 to 5.10.1984 (Тда-conat and Dst varies from 26 to -39) +О.І2пг+О.ЩпѴ*)г T herefore it could be expected that the monotonous dependence of Ag_w o n Dst would be again step-like w h e n excluding the substorm interval from our statistical consideration. Indeed the detailed analysis shows that out of the interval of the storm activity the negative changes in Dst abruptly decrease the amplitudes of the pulsations wh i c h are excited, i.e. as if they further their damping. The negative changes decrease the amplitude n o matter whether they are in the forenoon or afternoon sector. Wi t h i n the 18-24 UT interval the pulsations amplitude is usually zero j the positive changes in Dst does not alter the picture, i.e. A=0. DISCUSSION OF THE RESULTS. The mathematical-statistical studies of the dependence of the amplitudes A o n Dst and its variations indicate the predo minant influence on Dst during the ma i n phase of the substorm and the determ ining role of A Dst than of Dst out of this interval (Pigures 3,4). Together w i t h the solar wi n d velocity (V^y) controlling factor, Dst also appears w h i c h therefore shows the relation of the pulsation activity at middle lati tudes w i t h the geomagnetic phenomena at polar latitudes. The positive ДDst support the occurrence and duration of the pulsations and vice versa their a bsorption is expected to be stronger and more effective at negative changes of Dst. The dependence of A on ЛDst can be interpreted as a decrease of the pulsations durations: very often at negative A Dst the duration is less than a n hour, or their amplitude strongly varies. The establishment of a relation b etwee n A an d Dst indicates an eventual dependence between the wave growth rate and Dst. Therefore the following problems arise: 1) H o w do the oharac- terietics of the ring current change at positive variations of Dst. Is the pulsations increase connected w i t h the loss of particles from this current? 2) Is the nonpropagation of the mid-latitude pulsations (with period < 40 s) after 18 hours connected w i t h the particular structure of the plasmapause of the dusk side? If the intensification of the proton component of the ring current is the cause of wave damping, what is it that excites them? The N-S Component of the pulsations does not depend on ДDst unlike the E- W compon ent. Is this connected w i t h the ionospheric conductivities? I05