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.

N.P. Perevalova at al. velocity component Уф decreases from polar latitudes to the equator. The effect is more evident at the geomagnetic longitudes near 90° and 270°. The meridional velocity component Vr in the geomagnetic longitudes near 0° and 180° slightly varies with latitude and is close to the meridional velocity in the geomagnetic coordinate system. At other longitudes, the meridional component Vr tends to increase (from ~250 to ~617 m/s) as the latitude decreases. 3. Discussion If LS TIDs (occurring in the auroral zone during magnetic storms) travel along geomagnetic meridians, it is reasonable to expect that the propagation velocity of these disturbances (calculated in the geographic coordinate system) has the above peculiarities. We compared the simulation results with data on LS TID motions obtained in [Afraimovich et al., 2000; Leonovich et al., 2004, Perevalova et al., 2008]. The condition of LS TID propagation along the geomagnetic meridian is satisfied in the American and Far Eastern regions: Уф is small near the Zero Magnetic Meridian increasing with distance away from it [Afraimovich et al., 2000; Perevalova et al., 2008]. The statistics for five magnetic storms [Leonovich et al., 2004] supports the assumption of the meridional propagation too. An analysis of the table in [Leonovich et al., 2004] shows that westward deviations on the dayside were obtained in the American region; eastward deviations on the night side, in the European and Asian regions. However, a westward deviation was registered in the European and Asian sectors during the 29 October 2003 storm [Perevalova et al., 2008]. This contradicts the above assumption, requiring further study. 4. Conclusion We simulated the motion of points in the geomagnetic and geographic coordinate systems. In the geographic coordinate system, the point moving along the geomagnetic meridian is shown to have two components (the meridional Vr and the zonal Уф ones). The value of Уф decreases from polar latitudes to the equator. At meridians with a geomagnetic longitude of 0° and 180°, Уф is 0. At geomagnetic longitudes from 0° to 180°, Уф is eastward; at geomagnetic longitudes from 180° to 360° it is westward. If LS TIDs travel along geomagnetic meridians, their propagation velocity (calculated in the geographic coordinate system) should have the above-mentioned peculiarities. Experimental data on direction of auroral LS TIDs travel suggest that these disturbances propagate along magnetic meridians in the American and Far Eastern longitudinal sectors. A cknow ledgem ents. This work has been supported by the Russian Foundation for Basic Research (grant No. 08-05-00658). References Afraimovich E.L., Kosogorov E.A., Leonovich L.A., Palamarchouk K.S., Perevalova N.P., Pirog O.M. (2000), Determining parameters of large-scale traveling ionospheric disturbances of auroral origin using GPS- arrays, J. Atmos. Sol. Terr. Phys., 62(7), 553-565.2000. Afraimovich E.L., Perevalova N.P. GPS monitoring of the Earth’s upper atmosphere. Irkutsk 2006.480 p. Balthazor RL., Moffett RJ. Morphology of large-scale traveling atmospheric disturbances in the polar thermosphere, J. Geophys. Res., 104(A1), 15-24, doi: 10.1029/1998JA900039.1999. Ding F., Wan W., Liu L., Afraimovich E.L., Voeykov S.V., Perevalova N.P. A statistical study of large-scale traveling ionospheric disturbances observed by GPS TEC during major magnetic storms over the years 2003- 2005, J. Geophys. Res., 113, AOOAOl, doi: 10.1029/2008JA013037.2008. Ding F., Wan W., Ning B., Wang M. Large-scale traveling ionospheric disturbances observed by GPS total electron content during the magnetic storm of 29-30 October, 2003, J. Geophys. Res., 112, A06309, doi:10.1029/2006JA012013.2007. Foster J.C., Turnnen Т., Pollari P., Kohl H., Wickwar V.B. Multi-radar mapping of auroral convection, Adv. Space Res., 9(5), 19-27.1989. Hajkowicz L.A. Global onset and propagation of large- scale travelling ionospheric disturbances as a result of the great storm of 13 March 1989, Planet. Space Sci., 39, 583-593. doi: 10.1016/0032-0633(91)90053-D. 1991. Hall G. E., Cecile J.-F., MacDougall J.W., St.-Maurice J.P., Moorcroft D.R. Finding gravity wave source positions using the Super Dual Auroral Radar Network, J. Geophys. Res., 104(A1), 67-78, doi:10.1029/98JA02830. 1999. Leonovich L.A., Afraimovich E.L., Portnyagina O.Yu. Propagation velocities and propagation directions of large-scale disturbances of total electron content during strong magnetic storms, Geomagnetizm i aeronomiya, 44(2), 166-173.2004. Maeda S., Handa S. Transmission of large-scale TIDs in the ionospheric F2-region, J. Atmos. Terr. Phys., 42, 853-859, doi: 10.1016/0021-9169(80)90089-6.1980. Perevalova N.P., Afraimovich E.L., Voeykov S.V., Zhivetiev I.V. Parameters of large-scale TEC disturbances during the strong magnetic storm on 29 October 2003, J. Geophys. Res., 113, A00A13, doi: 10.1029/2008JA013137.2008. 40