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.

N. G. Kleimenova et al. The intensification of FACs of the magnetospheric Region 1 (Rl) [lijima and Potemra, 1976] could be another plausible source of a dayside polar substorm. Such currents have be mapped into the closed magnetosphere in the morning and into the LLBL area near noon [ Wing S. et al., 2010]. Note, Feldstein et al. [2006] showed that the daytime polar electrojet (PE) can be interpreted as ionospheric currents linking the westward {WE) and eastward {EE) current systems (see Fig. 6). Really, sometimes during daytime polar substorms, there were small magnetic disturbances in the morning sector and in the evening one as it is seen in Fig. 3. Summary The turn o f the IMF Bz to the positive values under strong solar wind dynamic pressure can provide the conditions for developing a specific dayside high-latitude bay-like magnetic disturbances which we call “ dayside polar substorms". This substorm is developed in the vicinity o f the poleward boundary of aurora oval, probably, inside the closed magnetosphere. The daytime polar substorms are accompanied by the high-latitude field aligned currents enhancement and the change of the high-latitude ionospheric convection distribution. However, a source o f these FACs is still unknown. Acknow legments. This work was partly supported by the Program № 28 of the Presidium o f the Russian Academy of Sciences. References Anderson B.J., Takahashi K., and Toth B.A., Sensing global Birkeland currents with Iridium engineering magnetometer data, Geophys. Res. Lett., 27,4045-4048, doi:10.1029/2000GL000094, 2000. Friis-Christensen E., and Wilhjelm J. Polar cap currents for different directins of the interplanetary magnetic field in the Y-Z plane, J. Geophys. Res., 80 (10), 1248-1260, 1975. Feldstein Y.I. Magnetic field variation in near-pole region during magnetically quiet periods and interplanetary magnetic fields, Spacc Sci. Rev., 18, 777-861, 1976. Feldstein Y.I., Popov V.A., Cumnock J.A., Prigancova A., Blomberg L.G., Kozyra J.U., Tsurutani B.T., Gromova L.I., and Levitin A.E. Auroral electrojets and boundaries of plasma domains in the magnetosphere during magnetically disturbed intervals, Ann. Geophys, 24, 2243-2276, 2006 Gromova L.I., Kleimenova N.G., Levitin A.E., Gromov S.V., Drcmukhina L.A., and Zelinskii N.R. Daytime geomagnetic disturbances at high latitudes during a strong magnetic storm of June 21-23, 2015, Geomagn. Aeron. (Engl.Transl.), 56 (3), 281-292, 2016. lijima, Т., and T. A. Potemra, Field-aligned currents in the dayside cusp observed by Triad, J. Geophys. Res., 81(34), 5971-5979,1976. lijima Т., Potemra T.A., Zanetti L.J., and Bythrow P.F., Large scale Birkeland currents in the dayside polar region during strongly northward IMF: A new Birkeland current system, J. Geophys. Res.,89 (A9), 7441. doi: 10.1029/JA089iA09p07441, 1984. Iwasaki N., Localized abnormal geomagnetic disturbance near the geomagnetic pole and simultaneous ionospheric variation, Rep. Ionos. Space Res. Japan., 25,163-186. 1971. Kleimenova N.G., Antonova E.E., Kozyreva O.V., Malysheva L.M., Kornilova T.A., and Kornilov I.A. Wave structure of magnetic substorms at high latitudes. Geomagn. Aeron. (Engl. Transl.), 52, 746-754. 2012. Kleimenova N.G., Gromova L.I., Dremukhina L.A., Levitin A.E., Zelinskii N.R., and Gromov S.V. H ighlatitude geomagnetic effects of the main phase of the geomagnetic storm o f November 24, 2001 with the northern direction of IMF, Geomagn. Aeron. (Engl. Transl.), 55, (2), 174-184,2015. Levitin A.E., Kleimenova N.G., Gromova L.I., Antonova E.E., Dremukhina L.A., Zelinsky N.R, Gromov S.V., and Malysheva L.M. Geomagnetic disturbances and pulsations as a high latitude response to considerable alternating IMF variations during the magnetic storm recovery phase (Case Study: May 30, 2003), Geomagn. Aeron. (Engl. Transl), 55(6), 755-768, 2015. Rout D., Chakrabarty D., Sekar R., Reeves G.D, Ruohoniemi J.M, Pant Т.К., Veenadhari B., and Shiokawa K. An evidence for prompt electric field disturbance driven by changes in the solar wind density under northward IMF Bz condition, J. Geophys.Res. Space Physics, 121,4800-4810, doi:10.1002/2016JA022475. 2016 Wing, S., S. Ohtani, P. T. Newell, T. Higuchi, G. Ueno, and J. M. Weygand Dayside field- aligned current source regions, J. Geophys. Res., 115, A12215, doi:10.1029/2010JA015837, 2010. 2 6