ИСТИНА

Since the first observations of the solar wind made by the interplanetary missions Luna-1, -2, and -3 in 1959 [1, 2] , the pioneering works of K.I. Gringauz made fundamental contribution to our understanding the influence of the solar wind to the magnetospheric dynamics, now known as the space weather. At the first stages of space weather research, the solar wind velocity was considered as the main factor controlling the geomagnetic activity. K.I. Gringauz studied the correlation between the yearly averaged parameter of geomagnetic activity aa and the solar wind velocity for the 20 solar cycle, and showed that they are highly correlated [3]. However, he also noticed that such good correlation might not persist for other solar cycles. This prediction was confirmed later, when it was found that the high correlation breaks down for the cycles 21 and 22 [4]. Even these early works revealed the principal limitations of the most popular models of the creation of magnetospheric convection: the reconnection model developed by Dungey [5] and the viscous interaction model developed by Axford and Hines [6]. The first model postulated the validity of the frozen-in condition, which could be destroyed only in definite points and lines. The second model is based on the alternative physical principles and suggests the development of strong turbulence and appearance of great viscosity due to development of instabilities at the magnetospheric flanks. The model of Boris Tverskoy [7] developed later had no such limitations. It considered the formation of large-scale magnetospheric convection as a result of the inner magnetospheric instability development (see the review [8]). It was able to predict the configuration, location and value of later discovered field-aligned current system. Unfortunately, the influence of the solar wind parameters on the magnetospheric convection was not considered in this model. On the other side, the Dungey model suggested the explanation of the dependence of geomagnetic activity on the orientation of the interplanetary magnetic field (IMF), obtained by many researches, including [4], that made it very popular for a very long time. However, its predictions are incompatible with the observed pressure balance at the magnetopause [9]. They also are in a strict conflict with the observed high level of turbulence in the magnetosheath and plasma sheet. In the turbulent regions, where the amplitude of magnetic field fluctuations is comparable with the averaged field, the magnetic field line often changes its topology, which might be interpreted as “reconnection phenomena” at the magnetopause or in the tail. This reconnection is widely considered as the main cause of magnetospheric activity (substorm development), but the constant change in the field line topology makes this statement rather questionable. Another difficulty is related to a low correlation between the solar wind-magnetosphere coupling functions and geomagnetc indexes. Newell et al. [10] analyzed more than 20 coupling functions and suggested a new one. Despite all this efforts, the correlation coefficients of such functions and geomagnetic indices are still not very high. The attempts to explain the reason of low correlations was not successful. This means that not all factors determining the geomagnetic activity were taken into account. Low values of correlation coefficients between coupling functions and geomagnetic indices show from one side the absence of the adequate information about parameters of plasma and magnetic field at the magnetospheric boundary, and from the other side the absence of the adequate information about magnetospheric dynamics and interconnections of different magnetospheric processes. The difficulties of conventional theories of geomagnetic activity require the development of new approaches, which do not request the validity of the frozen-in conditions. They should take into account the fact that the plasmas in the magnetosphere are in magnetostatic equilibrium when plasma velocity is much lower than sound and Alfven speeds. We summarize the latest achievements in this direction, including the results of the studies of turbulent transport in the magnetospheric tail, determining the localization of the auroral oval mapping to the equatorial plane, structure of transverse currents in the magnetosphere and nature and location of field-aligned currents [11]. We study the properties of isolated substorms, their dependence on solar wind and IMF parameters and connections to ring current dynamics [12]. We try to show that obtained results permit to reanalyze the main properties of magnetospheric dynamics and its connection to the solar wind and IMF parameters. Acknowledgments. The work was supported by RFBR grant 18-05-00362. References: [1] Gringauz K.I., Bezrukikh V.V., Ozerov V.D., Rybchinskii R.E. A study of the interplanetary ionized gas, high-energy electrons, and corpuscular radiation from the Sun by means of the three-electrode trap for charged particles on the second Soviet cosmic rocket // Dokl. Akad. SSSR. 1959. V. 131. No. 6. p. 1301. [2] Gringauz K.I., Bezrukikh V.V., Ozerov V.D., Rybchinskii R.E. A study of the interplanetary ionized gas, high-energy electrons, and corpuscular radiation from the Sun by means of the three-electrode trap for charged particles on the second Soviet cosmic rocket // Sov. Phys. Dokl. 1960. V. 5. P. 361–364. [3] Gringauz K.I. Average characteristics of the solar wind and its variation during the solar cycle, in Solar Wind Four, Rep. MPAE-W-100-81-31, edited by H. Rosenbauer, Max-Planck-Institut, Katlenburg-Lindau, Germany. 1981. P. 84-95. [4] Crooker N.U., Gringauz K.I. On the low correlation between long-term averages of solar wind speed and geomagnetic activity after 1976 // J. Geophys. Res. 1993. V. 98. No. A1. P. 59-62. doi:10.1029/92JA01978 [5] Dungey J.W. Interplanetary magnetic field and auroral zone // Phys. Rev. Lett. 1961. V. 6. No. 1. P. 47-49. [6] Axford W.C., Hines C.O. A unifying theory of high latitude geophysical phenomena and geomagnetic storms // Can. J. Phys. 1961. V. 39. No. 10. P. 1433-1464. [7] Tverskoy B.A. Electric fields in the magnetosphere and the origin of trapped radiation // Solar-Terrestrial Physics, edited by E. R. Dyer, Dordrecht, Holland. 1972. P. 297-317. [8] Antonova E.E., Tverskoy B.A. On the nature of electric fields in the Earth’s inner magnetosphere (a review) // Geomagnetism and Aeronomy International. 1998. V. 1. No 1. P. 9-21. [9] Sibeck D.G., Lopez, R.E., Roelof, E.C. (1991) Solar wind control of the magnetopause shape, location and motion // J. Geophys. Res. V. 96. P. 5489–5495. doi:10.1029/90JA02464 [10] Newell P.T., Sotirelis T., Liou K., Meng C.-I., Rich F.J. A nearly universal solar wind-magnetosphere coupling function inferred from 10 magnetospheric state variables // J. Geophys. Res. 2007. V. 112. doi:10.1029/2006JA012015. [11] Antonova E.E., Stepanova M., Kirpichev I.P. et al. Structure of magnetospheric current systems and mapping of high latitude magnetospheric regions to the ionosphere // Journal of Atmospheric and Solar-Terrestrial Physics. 2017. doi:10.1016/j.jastp.2017.10.013 [12] Vorobjev V.G., Yagodkina O.I., Antonova E.E., Zverev V.L. Influence of solar wind plasma parameters on the intensity of Isolated magnetospheric substorms // Geomag. Aeron. 2018. V. 58. No. 3. P. 295–306.