Physics of auroral phenomena : proceedings of the 33rd Annual seminar, Apatity, 02 - 05 March, 2010 / [ed.: A.G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2011. - 206 с. : ил.

Physics o fAuroral Phenomena", Proc. XXXIIIAnnual Seminar, Apatity, pp. 3 7 - 40, 2011 Polar © Kola Science Centre, Russian Academy of Science, 2011 hi/jU j Geophysical \ V J Institute IONOSPHERIC DISTURBANCES GENERATED IN THE AURORAL ZONE DURING MAGNETIC STORMS N.P. Perevalova1, S.V. Voyeikov', V.S. Batozskaya2 and D.S. Trynkova2 1. Institute o f Solar-Terrestrial Physics (ISTP) SB RAS, Irkutsk, Russia 2. Irkutsk State University, Irkutsk, Russia Abstract. Deviation of large-scale traveling ionospheric disturbances (LS TIDs) from the equatorward propagation direction is discussed. These LS TIDs are registered in the auroral zone during magnetic storms. The deviation is a well- known phenomenon, but its causes are still unclear. The LS TID motion along the geomagnetic meridian may be a possible cause. In order to check this hypothesis, we simulated motion of the points in the geographic and geomagnetic coordinate systems. If a point travels along the geomagnetic meridian, its velocity has two components in the geographical coordinate system: along the geographical meridian (meridional component) and along the geographical parallel (zonal component). The values of meridional and zonal components vary with longitude and latitude. 1. Introduction When studying the ionospheric response to magnetic storms, special attention is given to large-scale traveling ionospheric disturbances (LS TIDs) with characteristic time periods of 1-2 hours and wavelengths of 1000-2000 km [Maeda and Handa, 1980; Balthazor and Moffett, 1999; Afraimovich and Perevalova, 2006; Ding et al., 2007; Ding et al., 2008]. These LS TIDs are generated at the southern boundary of the auroral oval and propagate from high to middle and low latitudes with phase velocities of 600-900 m/s [Hajkowicz, 1991; Perevalova et al., 2008; Ding et al., 2007; Ding et al., 2008]. Geomagnetic Coordinates Geomagnetic longitude: • 0 ° A 15° ■ 90° Ж 105° A 165° \ / J L . x " V о ««по 1 3 5 V S > V r ' / 225 C 180 W ~ Д у г 1 x 240° \ I T 1 Ф 150 ^ 4 ^ . I 210 1 270° 165 180 195 * 285° Fig. 1. Simulation of motion of points along nine geomagnetic meridians (0°, 15°, 90°, 105°, 165°, 180°, 240°, 270°, 285°) in the geomagnetic coordinate system. 37