Physics of auroral phenomena : proceedings of the 40th annual seminar, Apatity, 13-17 March, 2017 / [ed. board: N. V. Semenova, A. G. Yahnin]. - Апатиты : Издательство Кольского научного центра РАН, 2017. - 143 с. : ил., табл.

Semi-centennial north-south displacements o fthe HCS based on the reconstructed IMF sector structure i stands for the geomagnetic station, H and D are horizontal component and declination of the geomagnetic field. Figure 1. Schematic scenario of the sign change in the asymmetry of solar magnetic fields and offset of solar dipole, (a) Yellow fill color the sunspot numbers. Solar minima are marked as T. (b) Radial polar field component in the hemispheres. North is colored in light blue and south in light red. (c) Schematic asymmetric current sheet, (d) Asymmetry of days with negative (T) and positive (A) IMF polarities. Vertical dashed grey lines show solar minima. To (dashed red line) defines the sign change of the asymmetry. During satellite era, we determine the success rate o f the polarity proxies as the percent o f correct daily polarities. Assuming the 45 degree angle of the Parker spiral at 1 AU, the actual IMF polarity can be defined as the sign o f the (By-Bx) expression in GSE coordinate system. For data sets 1 - 6, we obtain 79.5, 80.3, 82.4, 82.5, 85.4, and 87.9% success rates, i.e. the more geomagnetic variations are used to obtain polarity proxy the more correct result will be. ^340 1880 1880 1900 1920 1940 1960 1980 2000 Year Figure 2. (a) Annual ratio of negative (T) and positive (A) polarity days according to polarity proxies Set 1-6 and from the satellite IMF data (BG se ); dashed curve - approximate ТА wave (b) Yellow fill color the annual sunspot numbers. Cycle numbers refer to the Ztirich numbering. To assess the superiority o f one IMF polarity, we calculate the annual ratio according to the formula: T ~ A ТА = —— - T + A 87