Physics of auroral phenomena : proceedings of the 37th Annual seminar, Apatity, 25 - 28 February, 2014 / [ed. board: A. G. Yahnin, N. V. Semenova]. - Апатиты : Изд-во Кольского научного центра РАН, 2014. - 125 с. : ил., табл.

N.A Barkhatov et al. activity. Furthermore, since the Solar sources of magnetic clouds are spot groups, located mainly in the areas of "royal" latitude, then due to changes Earth's gelioprojection on the Solar disk, the frequency of occurrence of ejection in the vicinity of the Earth should increase during the equinox. Verification of this hypothesis seasonal dependence of geomagnetic activity performed on the data on the orientation of 52 magnetic clouds, registered in the near-Earth from 1980 to 2004 according to the system OMNI. 2. Axial hypothesis for magnetic clouds o f Solar wind Investigation of the effect o f the Sun rotation axis inclination to the Sun-Earth line for seasonal variation of geomagnetic activity within the proposed hypothesis based on the directory of solar flares, coronal mass ejections (http://-mvMi.ngdc.noaa.gov/stp/SOLAR/ftpsolaiflares; html; daw.gsfc.nasa.gov/CMEJist/index.html) and data on the global geomagnetic activity (Dst-index) was conducted for the period from 1980 to 2004. On the basis of these directories Solar sources and their coordinates for the 52 considered magnetic clouds were installed. Checking the axial hypothesis for magnetic clouds in the framework of the statistical analysis of the latitude Solar sources distribution in times of equinoxes and solstices was carried out (Fig. 2). The analysis carried out the presence of a "shift" for latitude Solar sources in the areas of active regions («royal» latitudes) during equinox and symmetrical distribution during periods solstice are showed. The resulting latitude distribution an increase in geomagnetic activity due to higher probability of meeting the Earth's magnetosphere with plasma flows during periods of equinox was shows. Vernal equinox Autumnal equinox Range Solarsours latitude, deg Range Solar sours latitude, deg Winter solstice I s »• ! ! 1 i n ... !? Я 2 2 ^ ° л S S 8 S si Я ? о •* ©«о 8 * S 2 ^ 15ЙS Summer solstice ,> a I "§1 Й.2 III I .1 Range Solar sours latitude, deg Range Solar sours latitude, deg Figure 2. Latitude distribution of magnetic clouds sources by seasonal 3. Seasonal dependence o f geomagnetic activity on the magnetic cloud structures Investigation of the effect of the magnetic cloud orientation on the seasonal variation of geomagnetic activity on the basis of analysis of the ratio (percentage) of geoeffective and not geoeffective clouds of different orientations around the equinoxes and solstices carried out (Fig. 3, gray bars - geoeffective, black bars - not geoeffective clouds). All viewed magnetic clouds into three groups according to the angle e: from 0 to 30°, from 30 to 60° and 60 to 90° were divided. In Fig.3 each range values o f s corresponds to 100%. 0 -3 3 20 - 60 » - Ranges o f angle e variation, deg Ranges of angle e variation, deg Figure 3. The ratio o f geoeffective (gray bars) and not geoeffective (black bars) magnetic clouds of the Solar wind for intervals of the angle £ from 0° to 30°, from 30° to 600, from 60° to 90° in percent Solstice The resulting distribution the contribution in geoeffectiveness of each of the ranges values of the angle e allows us to estimate. Since magnetic clouds with large (60 - 90°) axis angles to ecliptic plane geomagnetic disturbances in 85% of cases in the solstice periods and 40% of the equinoxes are caused. Magnetic clouds with small angles for 79