SINP MSU Report for IAGA

Skobeltsyn Instytute of Nuclear Physics

Moscow State University

NPI MSU, 119899,Moscow,Russia

Tel: 7(095) 9390896

Fax: 7 (095) 9391818

Director - Professor Mikhail I. Panasyuk

Theoretical and Applied Space Physics Department
Division III: Magnetospheric Phenomena.

Main results of the theoretical research of magnetospheric processes are as follows:

The structure of the magnetic storm ring current was calculated using the empirical relationship between the Dst-variation amplitude and the intensity maximum of the relativistic electron belt arising on the recovery phase of the storm (Tverskoy 1997).
Using the analysis of equal magnetic flux tube volume configurations it was shown that there is the powerful high latitudinal quasi-ring current together with the well known magnetospheric current systems (Antonova and Tverskoy 1998, Antonova and Ganushkina 1997).
Modelling processes of formation of magnetospheric tail plasma sheet was executed with consideration of development of middle scale turbulence in the plasma sheet (Antonova and Ovchinnikov 1998).
The characteristic time of particle motion chaotisation was determined under various parameters of the problem. The three-dimensional model of plasma distribution in the magnetospheric tail was created (Antonova and Ovchinnikov 1997).

The basic results of experimental study of dynamics of outer radiation belt relativistic electron fluxes, ring current ion fluxes and near-Earth plasma sheet hot plasma fluxes are as follows:

Using the data from the GLONASS satellite (circular orbit ã 20000 km, i=65ˆ ) the variations of relativistic electron fluxes of the outer radiation belt were researched for the solar activity minimum. The seasonal variations of electron intensity were discovered in the outer radiation belt (Ivanova 1999). Parameters of several, registered after magnetic storms, diffusion waves of relativistic electrons correspond to the diffusion theory under the action of sudden impulses.
For the first time, it was shown that relativistic electrons can be injected into the slot region during the substorm for ~ 1 hour. The location of the maximum (Lmax) of the relativistic electron belt, having formatted as a result of magnetic storm and of the centre of the western auroral electrojet in the moment of its extreme approach to the Earth during the substorm, corresponds very well with the dependence (Tverskay 1998):

(D_st)_max=2.75* 10⁴/L⁴_max

Using the data from the GORIZONT satellite (the geostationary orbit) several characteristics of near-Earth plasma sheet hot magnetospheric plasma were studied (Ivanova 1996).
From the same data several features of energetic spectra and dynamics of ion H⁺, He⁺⁺ and O⁺ ring current in the energy range from 41 to 133 keV/Q were studied (Kovtyukh 1996).
Using simultaneous data from the two GORIZONT satellites several features of charged particles were studied under the long period of northward interplanetary magnetic field (Vlasova 1999).

Antonova E.E. and Ganushkina N.Yu. Azimuthal hot plasma pressure gradients and dawn-dusk electric field formation, Journal of Atmospheric and Terrestrial Physics, V 59, N 11, pp. 1343-1354, 1997

Antonova E.E. and Ovchinnikov I.L., The inner magnetosphere source of dawn-dusk electric field and magnetospheric dynamics, Adv. Space Res., V 19, N 12, pp. 1919-1922, 1997.

Antonova E.E. and Tverskoy B.A., On the nature of electric fields in the Earth's inner magnetosphere, Geomagnetism and Aeronomy International, 1998, V 1, N 1, pp. 9-21.

Antonova E.E. and Ovchinnikov I.L., Quasy three dimensional model of equilibrium turbulent plasma sheet in thebEarthôs magnetosphere tail and its substorm dynamics, Geomagnetism & Aeronomy, 1998, V.38, N 5, pp. 14-21.

Ivanova T.A., Kutuzov Yu.V., Marjin B.V., et al., Some characteristics of hot magnetospheric plasma at geostationary orbit, Geophysical Monograph., series of AGU, 1996, V 97, pp. 269-274.

Ivanova T.A., Pavlov N.N., Reizman S.Ya., et al., Dynamics of the relativistic electron outer radiation belt, Geomagnetism & Aeronomy, 1999 (in press, Russia)

Kovtyukh A.S., Martinenko G.B., Sosnovets. E.N., et al. Variations of the intercomponent ring current energy spectra during the geomagnetic storms: õGorizont-35æ results, Adv. Space Res., 1996, V.17, N 2, pp.179-182.

Tverskay L.V. Diagnosing the magnetospheric processes using radiation belt relativistic electron data, Geomagnetism & Aeronomy, 1998, V. 38, N5, pp.22-32

Tverskoy B.A. Formation mechanism of the structure of the magnetic storm ring current, Geomagnetism & Aeronomy, 1997, V 37, N5, pp. 29-34.

Vlasova N.A., Kovtyukh A.S., Kutuzov Yu.V., et al., Observations at geosynchronous orbit of near plasma sheet, ring current and radiation belt energetic electrons on March 11-25, 1992, Kosmich. Issled., 1999 (in press)

Department of Radiation and Computational Methods
Division III: Magnetospheric Phenomena.

The new concept of the magnetosphere-ionosphere system dynamics was developed. The concept is based on the principles of non-linear dynamics and catastrophe theory, as well as on the kinetic plasma theory, determining the structure of thin current sheets in plasma and their dynamics.
"Soft" and "rigid" modes of instability responsible for the catastrophe of plasma sheet equilibrium have been studied, which determine the explosion-like phase of the geomagnetic tail dynamics - substorm activation. The detailed theory of the non-linear tearing-instability is elaborated; that appears to be possible due to a specific effect in the electron dynamics in the sheet: preferential electron acceleration at the boundary between dynamical chaos and adiabatic regions in the phase space. It is found out that mechanisms of cross-field current instabilities generating small-scale turbulence, are capable to render a feedback for large-scale instabilities of tearing-mode type. For the model of extremely thin anisotropic equilibrium current sheet, a complete theory has been constructed; which allows using it as the basic model in the magnetospheric physics. The role was clarified of this non-linear structure at the developed stage of a substorm activation, providing a fast transformation of magnetic field energy stored in the tail, into the energy of plasma flows.
The developed theoretical approaches favourably agree with observational data and allow resolving a number of controversies with explanation of large-scale geomagnetic disturbances.

Kropotkin A.P.,M.I.Sitnov, Magnetospheric substorm dynamics from the viewpoint of open nonlinear systems theory, in "Problems of Geospace", edited by M.I. Pudovkin, B.P. Besser, W. Riedler, A.M.

Sitnov M.I., H.V.Malova, A.T.Y.Lui, Quasi-neutral sheet tearing instability induced by electron preferential acceleration from stochasticity, J.Geophys. Res., 1997, 102 (A1), 163-173.

Kropotkin A.P., H.V.Malova, M.I.Sitnov, The self-consistent structure of a thin anisotropic current sheet, J. Geophys. Res., 1997, 102 (A10), 22099-22106.

Sitnov M.I., H.V.Malova, A.S.Sharma, Role of temperature ratio in tearing

stability of the quasi-neutral sheet tearing mode, Geophys. Res. Letters, 1998, 25, No.3, 269-272.

Kropotkin A.P., O.O.Trubachev, A.T.Y.Lui, Nonlinear instability of the geomagnetotail current sheet combining the features of tearing and cross-field current instabilities, J. Geophys. Res., 1999, 104 (A4), 371-382.

Sitnov M.I., A.T.Y.Lui, Cross-field current instability as a catalyst of the explosive reconnection in the geomagnetotail, J. Geophys. Res., 1999, 104 (A4), 6941-6952.

Division IV: Solar Wind and Interplanetary Field.

Average solar wind and heliospheric magnetic field parameters at the Earth's orbit show specific solar cycle variations and longer-term trends during last three solar cycles. The five years solar wind density variation is found (Veselovsky et al., 1998).
The global heliolatitudinal and heliolongitudinal velocity pattern of the solar wind was found theoretically based on the gas-kinetic approximation. The strongest velocity difference between maximal and minimal values was shown to be observed at middle latitudes during 1994-95 (Veselovsky, 1995).

Veselovsky I.S., Large-scale solar wind stream structure at high heliolatitudes. Space Sci. Rev., V.72, p.87-92, 1995

Veselovsky I.S., A.V. Dmitriev, A.V. Suvorova, Average solar wind and interplanetary magnetic field parameters at the Earth's orbit during last three solar cycles. Solar System Research, V.32, p.310-315, 1998

Department of Space Physics Investigations
Division III: Magnetospheric Phenomena.

It has been demonstrated that the energetic electron trapping conditions are substantially variable in the inner radiation belt. There were separated L=1.3;1.6;2.3 where quasi trapped electron flux dynamics was investigated.

Kuznetsov S.N., Myagkova I.N. Anomalous fluxes of quasi-trapped electrons (>0.5 MeV)under the inner radiation belt.WDS`98 PII, University Karlovy, 1998, p 220-225.

The magnetic storm on April 17, 1994 caused sharp decrease of energetic electron and proton intensities in the outer radiation belt.

Gotselyuk Yu.V.,Kuznetsov S.N.,Sinyakov A.V. Changes of outer radiation belt structure during the magnetic storm of April 17, 1994. WDS`98 PII, Matfyzpress, Univerzity Karlovy, 1998, p 226-234.

Two geomagnetic substorm types were identified:
substorms, accompanied by relativistic electron enhancements in plasma sheet, and practically invariable Dst-index.
those, not accompanied by enhancements of relativistic electrons in plasma sheet, resulting in Dst- index decrease.

Gotselyuk Yu.V., Kuznetsov S.N., Sinyakov A.V. WDS`98 PII, Matfyzpress, Univerzity Karlovy, 1998, p 210-215.

On the basis of the data base by Sibeck and the data on registration of magnetopause on geostationary orbit from 1967 to 1992 two models of magnetosphere for P= 0.5-24 nPa; -20<Bz<20 nT were created:
the first is the parabolic model for Q <110ˆ,
the second - for Q <140ˆ .

Kuznetsov S.N. and A.V.Suvorova An empirical model of the magnetopause for broad range of solar wind pressure and IMF Bz in Polar Cap Boundary Phenomena NATO ASI Series C, p 51-61, 1998.

Kuznetsov C.N.,Syvorova A.V.,Dmitriev A.V. Form and Size of the Magnetopause. Connection with the space parameters. Geomagnetizm and Aeronomy. V38, N6.p7-16, 1998.

Empirical Artificial Neural Network models of solar wind - Earth magnetosphere coupling are presented on www page http://dec1.npi.msu.su/~alla.
3D dayside magnetopause model is developed using General Regression Neural Network (Kuznetsov et al.,1998).
The complex ANN system for modelling of solar-terrestrial links and consequences on near-Earth radiation dynamics is proposed and developed (Dmitriev et al., 1999).

Kuznetsov S.N, A.V. Suvorova, A.V. Dmitriev. Geomagnetism and Aeronomy, 38, 6, 7, 1998

Dmitriev, A.V. Yu.S. Minaeva, Yu. V. Orlov, I.G. Persiantsev, A.V. Suvorova, I.S. Veselovsky. Proc. of ESA Workshop on Space Weather, 11-13 November, 1998, ESTEC, Noordwijk, The Netherlands, 393, 1999

Division IV: Solar Wind and Interplanetary Field.

On the basis of the CORONAS-I and ULYSSES data it was found that the recurrent fluxes of~1 MeV protons measured during March-June 1994 were correlated at the both spacecraft. The appearance of the proton fluxes coincided with the co-rotating high-speed solar wind streams reaching the Earth's vicinity. The high-speed solar wind streams were
observed continually by Ulysses. One can suppose that the source of the proton fluxes is the shock on the front of high-speed stream formed at 3-5 AU. The observation of such fluxes by Ulysses can be explained if the magnetic field lines at the distance 15-20 AU approach the solar equator plain.

Veselovsky I.S., Gotselyuk Yu.V., Denisov Yu.I. et al. Recurrent energetic particle enhancements according to CORONAS-I data. Izv. Vuz. Radiophys.V.XXXIX, N11-12, p1527-1532, 1996.

Investigation of the solar energetic particle event on April 14, 1994 was carried out using the data from the CORONAS-I and IMP-8.One surprising feature of this event is that it was not associated with any solar flare. It has been proposed that energetic particles were accelerated on the front of bow shock driven by CME at 0.05-0.1 AU. This CME caused the geomagnetic storm on April 17,1994.

Kahler S.W., Cane H.V., H.S.Hudson, V.G.Kurt, Yu.V.Gotselyuk, MacDowall R.J.,and V.Bothmer The solar energetic particle event of April 14, 1994, as a probe shock formation and particle acceleration. J.G.R. V 103,NA6, p 12,069-12,076,1998.

Veselovsky I.S.,Gorselyuk Yu.V.,Dmitriev A.V., Kuznetsov S.N.,Viktoriya Kurt, Myagkova I.N., Oraevsky V.N., Panasyuk M.I., Podorolsky A.N., and Ryumin S.P. Kosmich. Issled. 1997, V35, N2, p 127-132.

The applications of Artificial Neural Networks (ANN) for modelling of the solar wind and interplanetary magnetic field dynamics are presented on www-page http://dec1.npi.msu.su/~alla . Long time (1999-2003) solar activity and heliospheric dynamics are predicted by means of Recurrent Neural Network (Dmitriev, 1999a). The dynamics of the solar wind and interplanetary magnetic field in the Earth vicinity during last three solar cycles is studied and modelled including the prediction aspect (Dmitriev, 1999b). These predictions are directly used for Russian Space Weather initiatives (Avdyushin et al., 1999) presented on Web site: http://alpha.npi.msu.su/RSWI/rswi.html.

Dmitriev A.V., Yu.V. Orlov, I.G. Persiantsev, M.O. Riazantseva, I.S. Veselovsky. Geophysical Research Abstracts, 24^th EGS General Assembly, V1, N3, p.17, 1999a.

Dmitriev A.V., Yu.V. Orlov, I.S. Persiantsev, A.V. Suvorova, I.S. Veselovsky. Geophysical Research Abstracts, 24^th EGS General Assembly, V1, N3, p.776, 1999b.

Avdyushin S., A. Belov, A. Dmitriev, et al. Russian Space Weather Initiatives, Proc. of ESA Workshop on Space Weather, 11-13 November, 1998, ESTEC, Noordwijk, The Netherlands, p. 185-197, 1999.