Структура и динамика полярных токовых систем : материалы международного симпозиума «Полярные геомагнитные явления», 25-31 мая, Суздаль, СССР / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : [б. и.], 1988.

on magnetic activity with their specific seasonal features: - the Russell-McPherron effect displayed in all modes of disturbances being maximum in equinox periodsj - the |By J effect most noticeable in occurence of convectlonal disturb ances being maximum in summer seasons) - the negative azimuthal component (By < 0) effect is operating seemingly all the year round. Such is the influence of B„ on occurence of the magnetic disturbances. 1 60 | ♦ What are the By effects in the amplitude of disturbances? This problem was examined by Murayama et al. (1980) who have studied the influence of By on Al index (being corrected by taking into account the effects of B z and V 0W) as a function of tilt angle Jf of the earth's dipole axis toward the sun-earth line. The results of this study are presented in Pig.7 where the maximum positive (negative) value jc corresponds to summer (winter) conditions. It may be seen that the corrected AL index in summer is larger by 20 nT than in winter and the activity in summer is higher for By < 0 than for By > 0. The By effects on occurence and intensity of magnetic disturbances in these peculia rities are similar. However Pig.7 also shows that AL index is in linear rela tion to В for all tilt angles X . It means that the absolute value |B | У J does not influence the magnetic disturbance intensity. In addition to this the positive By component turned out to be more effective that the negati-ve one in winter seasons. The results of Sergeev (1979) also show that the magnetio activity in the auroral zone is higher for B y > 0 in winter and for B y C 0 in summer whereas according to Metlyaev et al.(1982) the intensity of magnetic disturbances increases in spring and summer periods when component is positive. Thus we see that the IMP azimu thal component influences the magne tic activity in a complicated and an ambiguous manner. The reasons of a different influence in revealed effects of on the occurence of dis turbances and their intensity are not clear. They may arise as a result of inaccurate consideration of time delay of magnetic disturbances, indistinction of convection activity and triggerd substorms and some other reasons. The peculiarities and mechanism of By effects apparently require further investigations. 60 20 0 1 1...T~ L Г -] ♦ , .................................. X J - - v - * - L A A ] г 1 L A J - H - T q Г ^ 1 Г J - 1 L Г J _i__ j — i— - -21 0 -7 7 - 0 -6 -г B y Pig. 7. Dependence of AL/(B0+O.5)v‘: versus В for various ranges of the dipole t¥lt angle jt (Murayama et al., 1980 ). 123