P.O.Box 4026,Irkutsk, 664033, Russia

Tel.: 7(3952)46 02 65

Fax: 7(3952)46 25 57

e-mail: uzel@iszf.irk.ru

home-page: www.iszf.irk.ru

The principal fields of research at the Institute are solar physics and the physics of the interplanetary medium; the physics of the atmosphere and of the Earth's immediate interplanetary environment.

Specializing in research on the origin and dynamics of solar magnetic fields, solar flares and other active features on the Sun, the Institute gives also considerable study to the solar wind and cosmic rays.

The objects of investigation include the Earth's magnetosphere, electromagnetic field, ionosphere, upper atmosphere, and the ionospheric radio wave propagation.

The Institute's prime research objective is to trace, in an integrated approach, the initiation and development of disturbances in the near-terrestrial environment, from the origination of the disturbing factor on the Sun, including its propagation through the interplanetary medium, to the response of the high and mid-latitude atmosphere.

Meteorological and magnetic observations (the cradle of solar-terrestrial physics) in East Siberia began at the Magnetic meteorological observatory of Irkutsk in 1886. It was among the first scientific institutions in Siberia. Edward Stelling was appointed its Director. Throughout the period of its operation, the Irkutsk magnetic meteorological observatory was furnishing high-quality data on the Earth's magnetic field, and they were regularly published in the Records of the Nicholas Main Physical Observatory.

In 1931, the Irkutsk magnetic meteorological observatory was reorganized into a Scientific research institute; in 1936, it was transformed into the Irkutsk geophysical observatory.

After World War II, point-to-point radio communication was a major preoccupation in this country. To improve the communication reliability the information was required not only about the magnetic disturbance level but also about ionospheric conditions.

In 1956, the Irkutsk geophysical observatory was reorganized into the hydrometeorological observatory, and its magnetic division formed the basis for a new scientific organization, the Diversified magnetic ionospheric station.

In 1960, on the basis of the Irkutsk magnetic ionospheric station an Institute of a new profile for Siberia was established, the Siberian Institute of Terrestrial Magnetism,

Ionosphere and Radio Wave Propagation at the Siberian Division of the USSR Academy of Sciences (currently - the Institute of Solar-Terrestrial Physics SD RAS). The Institute matured and evolved under the direction of N.M.Erofeev, Corresponding Member of the Academy of Sciences of the Turkmen SSR, and V.E.Stepanov, Corresponding Member of the USSR Academy of Sciences. Since 1984, Academician G.A.Zherebtsov has been Institute Director. The main research areas of the new Institute were established such as the research on the magnetosphere, ionosphere and ionospheric propagation of radio waves, solar activity and associated phenomena in near-terrestrial space, solving applied problems, solar patrol, monitoring of the state of the ionosphere and geomagnetic field, prediction of radio communication conditions, and recording of cosmic rays.

The establishment of an Institute in Irkutsk doing research on problems in solar physics and the Earth's magnetosphere and ionosphere, i.e. problems of a planetary rather regional character, was motivated by the need to give further impetus to investigations, and by space exploration - it was really the dawning time of the space era then!

An impressive cluster of research equipment (nine observatories) has been created at the Institute, including unique facilities of international significance.

The Baikal astrophysical observatory includes the Large solar vacuum telescope designed to investigate the fine structure of solar features.

Three unique solar instruments are installed at the Sayan solar observatory: the horizontal solar telescope with the magnetograph, the coronagraph, and the solar telescope for operative predictions.

A turning point in furthering radio and astrophysical research was the development and construction of the unique Siberian solar radio telescope. For the creation of this instrument, the Institute's composite author was awarded the RF Government prize in the field of science and technology for the year 1996.

The Institute operates a radar facility for measuring ionospheric plasma parameters by the method of incoherent scatter of radio waves.

The ISTP SD RAS Space Monitoring Center is engaged observations of the dynamics of meteorological processes, the vertical distribution of energy parameters of the middle atmosphere, and of events on the terrestrial surface over small areas.

Owing to the complex of instruments, observatories and unique devices created in East Siberia, combined with highly qualified scientific personnel, the Institute is Russia's only scientific research establishment which is able to conduct experimental and theoretical research in almost the entire range of problems in solar-terrestrial physics.

For achievements in physical science and a great contribution to the solution of economic problems, by a Decree of the Supreme Soviet of the USSR of April 20, 1986, the Institute was awarded the Order of the Red Banner of Labor.

1. We were the first to obtain experimental corroboration of the predicted (by the theory of acoustic-gravity waves (AGW)) neutral wind-induced AGW filtering effect. Results of this research open up brand new vistas for neutral wind monitoring operations at ionospheric F-region heights using relatively simple radio probing facilities.

E.L.Afraimovich , B.O.Vugmeister, and A.D.Kalikhman. Adv. Space Res., 1996, V.18, No.3, p.121.

E.L.Afraimovich, O.N.Boitman, E.I.Zhovty, A.D.Kalikhman, and T.G.Pirog. Radio Science, 1998, V.34, No.2, p.477.

2. On the basis of analyzing satellite measurements of the total electron content (TEC) in the atmosphere on a global scale, it was possible to detect continental-scale "structures" and a systematic decrease in TEC over high mountain systems.

E.S.Kazimirovsky, and G.K.Matafonov. J.atmos.terr.Phys., 1998, V.60, No. 10, p.993.

3. Based on many years of uniform wind measurements in the mid-latitude lower thermosphere, a study was made of the geographic wind field nonzonality - systematic differences of the zonal and meridional wind and wave structure (planetary waves, tides), a dramatically different regional response to the external forcing (stratospheric warmings, geomagnetic storms, proton events), and different onset times of the springtime reversal of the zonal circulation. The wind field nonzonality which is not yet taken into account numerically in international reference models of the middle atmosphere, is interpreted as resulting from different conditions for generation and propagation of internal gravity waves from the lower atmosphere.

E.S.Kazimirovsky and G.V.Vergasova. Adv. Space Res., 1997, V.20, No.6, p.1233.

E.S.Kazimirovsky, G.V.Vergasova, and O.M.Pirog. Adv. Space Res., 1999 (in press).

4. A technique has been developed for studying traveling ionospheric disturbances, on the basis of receiving signals from the GPS (Global Positioning System) satellites.

E.L.Afraimovich, K.S.Palamartchouk, N.P.Perevalova. J.Atmosph.&Sol.-Terr. Phys., 1998, V.60, N12, p.1205.

5. The diagnostic complex including the incoherent scatter radar, the GPS-interferometer, and the chirp-ionosonde, was used to investigate, for the first time, the ionospheric response in the case of the superposition of two effects: passage of the terminator line, and solar eclipse. A maximum decrease in electron density was as low as 50% at altitudes of about 200 km (near the F-layer maximum), and in total electron content - 1-3 TECU; maximum deviations of electron temperature reached 30% at about 300 km altitudes. The delay of the F-layer and total electron content response to the eclipse was 10-15 minutes.

V.I.Kurkin, V.E.Nosov, A.P.Potekhin et al. Adv. Space Res., 1999 (in press).

E.L.Afraimovich, K.S.Palamarchuk, N.P.Perevalova et al. Geoph.Res.Lett., 1998, V.25, No.4, pp.465-468.

6. Spectral measurements were made of the ground-level solar ultraviolet radiation in the wavelength range 296-326 nm during the solar eclipse observed at Irkutsk on March 9, 1997.

The study revealed variations in the spectral distribution of the radiation recorded during the eclipse. It was suggested that changes in spectra observed at times close to the totality phase may be caused by the effect of multiple scattering of ultraviolet radiation.

A.V.Mikhalev, M.A.Chernigovskaya, A.B.Beletsky, E.S.Kazimirovsky. Advances in Space Research (in press).

7. In the polar ionospheric E-region, the magnetospheric substorm is accompanied by an increase in intensity and rigidity of precipitating fluxes in the Harang discontinuity, and by the equatorward displacement of the sporadic ionization zone at the beginning of the storm. After that, the electron density in the zone increases abruptly, and the zone itself undergoes a poleward expansion. The band of discrete precipitation lies inside the zone of diffuse precipitation of low-energy electron fluxes. Main current in the westward auroral electrojet flows not inside the region of maximum conductivity but significantly more northward of it, which corresponds to the region of minimum internal resistance of the magnetosphere.

G.A.Zherebtsov, O.M.Pirog, and V.D.Urbanovich. Adv. Space Res., 1997, V.20, No.9, pp.1693-1696.

O.M.Pirog and V.D.Urbanovich. Adv. Space Res. (submitted).

Division II. Magnetospheric Phenomena

1. We were the first to obtain information about the open magnetic flux dynamics in the course of substorms, based on traditional (in magnetospheric substorm research) database and using the magnetogram inversion technique which synthesizes observations from a worldwide network of ground-based magnetometers. A relevant new substorm scenario takes into account, in addition to the well-known mechanism of open-flux reconnection in the mid-tail, a further main mechanism operating in the near magnetospheric tail. Such a mechanism is either the closed magnetic flux reconnection or tail current partial disruption. A method for determining the open magnetic flux has also been developed for the flaring region on the Sun. The new scenario for large flares was found to be similar to the above-mentioned substorm scenario at the Earth: flares (such as LDE) have two sources spaced in altitude, with the same difference in basic physics as in the case of the substorm.

V.M.Mishin, A.D.Bazarzhapov, T.I.Saifudinova, S.B.Lunyushkin, D.Sh. Shirapov, L.Eliasson, J.Woch, L.P.Block, G.T.Marklund, L.G.Blomberg, and H.Opgenoorth. J.Geophys.Res., 1997, No. 9, pp.19845-19859.

V.M.Mishin, V.G.Banin, S.B.Lunyushkin, and C.-G.Falthammer. Proceedings of the ICS-3, ESA SP-389, 1996, pp.731-736.

V.M.Mishin and C.-G.Falthammer. Proceedings of ICS-4, Japan, 1998.

2. It has been established theoretically that plasma flow pressure variations of the solar wind arriving at the magnetosphere leads to magnetopause oscillations which are accompanied by global geomagnetic pulsations with periods of 6-8 min. Furthermore, the magnetopause oscillations cause a periodic variation in the shear flow MHD instability growth rate, which is distinguished in observations of daytime geomagnetic pulsations in the range of 10-60 s periods in the auroral and subauroral zones. Results of theoretical calculations are supported by an analysis of simultaneous observations by a series of satellites and from a network of ground-based stations.

V.A.Parkhomov, V.V.Mishin, and L.V.Borovik. Annales Geophysicae, 1998, V. 16, No.2, pp.134-139.

V.V.Mishin and V.A.Parkhomov. In: M.I.Pudovkin, B.P.Besser, W.Riedler and A.Lyatskaya (Eds.) "Problems of Geospace" (Proceedings of a Conference, Petrodvorets, St.Petersburg, Russia, June 17-23, 1996) ISBN 3-7001-X, 1997, pp. 107-111 V.A.

3. Theoretical investigations and results of plasma experiments on a laboratory device have shown that the transverse collisionless shock wave in plasma has the following structure: the region of hot electrons - the relaxation zone of some of the energy of the reflected ion flux - the region of diffusive growth of the magnetic field (footing) - a jump of parameters - the region behind the wave front. It was found that the ions reflected from the shock wave front play a decisive role for the formation of the shock wave itself. These ions play also an important role in the excitation of geomagnetic pulsations. The results obtained in this study, combined with satellite data, provide further insights into the understanding of the processes determining the structure of the front and the regularities of bow shock formation.

A.E.Indyukov, G.N.Kichigin, and N.A.Strokin. Phys. Let., 1996, V. A211, p.228.

N.A.Strokin, A.E.Indyukov, and G.N.Kichigin. J.Geophys.Res., V.103, A9, p.20541.

4. In collaboration with the Institute of the Physics of the Earth of RAS it has been shown that ponderomotive forces have a marked influence on the redistribition of ions along geomagnetic field lines under the action of Bc micropulsations.

The ponderomotive plasma redistribution along geomagnetic field lines below the polar caps under the action of travelling Alfven waves has been calculated. The study revealed a significant influence of ponderomotive forces on the polar wind acceleration.

A.V.Guglelmi, J.Kangas, K.Mursula, T.Pikkarainen, O.Pokhotelov, and A.S.Potapov. J.Geophys.Res., V.101, No.A10, 1996, pp.21493-21500.

Division III. Solar Wind and Interplanetary Field

1. It has been found that in each 11-year cycle of solar activity there exist two periods of fast (1-2 solar rotations) global changes in solar magnetic fields. Both periods are characterized by increased flaring activity which reflects rapid changes of magnetic structures recurring regularly in each 11-year cycle of solar activity; however, the peculiarities of the development and manifestations differ in their details from cycle to cycle. The detected changes in solar magnetic fields are accompanied by anomalous variations of solar wind parameters and of the interplanetary magnetic field, in cosmic-ray intensity and geomagnetic activity.

G.A.Zherebtsov and V.A.Kovalenko. Adv. Space Res., 1996, V.17, No. 4/5, pp. 335-340.

G.A.Zherebtsov, V.A.Kovalenko, and S.I.Molodykh. J.Geophys.Res., 1997, V. 102, No.A2, pp.2137-2145.

2. We have detected a new effect of anisotropic decrease in galactic cosmic ray intensity during the heliospheric propagation of intense proton fluxes of solar origin. It was concluded that an explanation for the results obtained requires that the propagation process of accelerated particles on the Sun should occur in self-consistent electromagnetic fields rather than in external fields.

V.M. Dvornikov and V.E.Sdobnov. J.Geophys.Res., 1997, V.102, No.A11, pp. 24209-24219.

V.M.Dvornikov and V.E.Sdobnov. Solar Phys., 1998, V.178(2), pp.405-422.

3. It has been shown that the generation of coronal mass ejections on the Sun is determined by the streamer belt and chain. Within distances R>(3-4)R' from the solar center, the field of streamers represents a sequence of radial rays with a typical angular diameter of 2-3 degrees, independent of R. These rays produce inhomogeneities of the material moving in the antisunward direction with velocities of 50-200 km/s.

The dynamics of coronal holes preceding the magnetic storm sudden commencement has been investigated.

V.G.Eselevich. Geophys.Res.Lett., 1995, V.22, p.2681.

V.G.Eselevich. J.Geophys.Res., 1998, V.103, A2, p.2021.

4. New techniques have been suggested for identifying coronal mass ejections in the solar wind, and estimates were made of the position of solar sources from solar wind characteristics at the Earth's orbit. A strong correlation was detected between the magnetic field amplitude in the magnetic cloud and solar wind characteristics ahead of the front of the shock wave excited by the magnetic cloud. A study was made of the correlation between coronal magnetic field variations and characteristics of coronal ejections.

V.G.Fainshtein and A.P.Kaigorodov. Planet. Space Sci., 1996, V 4, p.387.

V.G.Fainshtein, G.V.Rudenko, and V.V.Grechnev. Solar Phys., 1998, V.181, p.133.

Division IV. Geomagnetic Observations, Surveys and Analyses

Using the software package for HF signal reception based on oblique paths the Institute's geophysical observatory conducts regular observations with the purpose of determining the spatial structure of medium-scale ionospheric irregularities. The infrastructure has been developed, as well as the computer-aided facility for measuring characteristics of motion in the lower ionosphere, based on the LF broadcasting signal spaced-receiver method. Experimental investigations into atmospheric conditions are carried out using optical instruments (the 4-channel photometer, the TV-monitor, and the spectrometer for measuring the intensity of biologically active UF radiation).

Within the program of the incoherent scatter radar world observing days, regular observations are carried out using the incoherent scatter method and vertical-incidence sounding operations. Data sets have been obtained on densities, electron and ion temperatures, and ionospheric plasma velocities at F-layer heights. In accordance with the International Geophysical Calendar, experiments are underway with the purpose of investigating the ionospheric propagation of HF radio waves by the methods of oblique-incidence and backscatter sounding. In collaboration with the Laboratory of Military Technologies (Australia), an international experiment has been conducted on the investigation into the radio wave propagation through the transequatorial zone, and a system of paths was organized using chirp-sondes.

The experimental facilities of the Division of Magnetospheric Research are concentrated in the "Integrated geomagnetic observatory" which includes a number of stations carrying out a continuous monitoring in the following areas:

Magnetic observatory "IRKUTSK" (in operation since 1886):

* absolute measurements of the Earth's magnetic field elements;

* continuous digital recording of variations of the H-, D- and Z-components of the Earth's magnetic field.

Baikal magnetotelluric observatory "UZUR", and Sayan solar observatory "MONDY" (Magnetospheric Division):

* continuous observations of the state of the ionosphere;

* continuous observations of the variable constituent of the H-, D- and Z-components of the Earth's magnetic field;

* continuous recording of geomagnetic pulsations in the range of 0-5 Hz;

* observations of auroras;

* photometric observations of auroras using scanning photometers at different wavelengths.

Results of more than 100 years of observations at magnetic observatory "Irkutsk" were used to reconstruct the secular history of the H-, D- and Z-components of the Earth's constant magnetic field. Data on the values of the K-index and a catalogue of magnetic storms are entered into the Institute's server on a monthly basis.

http://ssrt.iszf.irk.ru/magnetic

In 1998, magnetic observatory "Irkutsk" joined the international association of magnetic observatories "INTERMAGNET", and data are supplied to its center on a daily basis.

Digital induction nanoteslometers with adjustment to the time received by the receiver from GPS satellites have been installed at observatories recording geomagnetic pulsations.

Further details may be obtained from

e-mail: rav@iszf.irk.ru