Restoration of the proton density distribution in the Earth’s plasmasphere from measurements along the INTERBALL-1 satellite orbit

Based on experimental data obtained in 1995?C2000 on board the INTERBALL-1 spacecraft using the ALPHA-3 instrument, a semi-empirical two-dimensional model of the Earth plasmasphere is developed, which allows for the plasma distribution in the entire meridional plane to be restored from the temperature and proton density measurements along the satellite orbit. The model has also been tested using the data of the IMAGE spacecraft. The model uses theoretical expressions (Lemaire and Schere, 1974) that describe the plasma distribution in the plasmasphere for the cases of thermal equilibrium and collisionless initial partial filling of plasmaspheric shells; therefore, the parameters of the constructed model have a clear physical meaning and make it possible, in particular, to estimate the degree of plasmasphere filling.     

Analytical model of the near-Earth magnetopause according to the data of the Prognoz and Interball satellite data

Based on the magnetopause observations near the Earth by the Prognoz/Interball satellites in 1972–2000, the empirical model of this boundary has been proposed, and the magnetopause behavior at different parameters of the oncoming solar wind has been studied. For the first time, it has been detected that the Earth’s magnetopause is compressed by ∼5% in the direction perpendicular to the plane including the vectors of the solar wind velocity and IMF. At the same time, any dependence of the subsolar magnetopause position on the IMF B _z component has not been revealed in the Progrnoz/Interball data. The proposed magnetopause model can be used to model the position and shape of the near-Earth bow shock.     

Results of Observations of Ionospheric Plasma Drift in the Polarization Jet Region

Geomagnetism and Aeronomy - Doppler measurement data from the Yakutsk subauroral ionospheric station have been used to reveal for the first time new and previously unknown dynamic phenomena during...     

Influence of geomagnetic storms of September 26–30, 2011, on the ionosphere and HF radiowave propagation. II. radiowave propagation

A study of HF wave propagation in the three-dimensional inhomogeneous ionosphere has been carried out in an approximation of geometrical optics. The three-dimensional medium of radio wave propagation is considered to be inhomogeneous, absorbing, and anisotropic due to the influence of the geomagnetic field. The parameters of the medium are described by the results of calculations on the basis of the Global Self-Consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP). The propagation of radio waves in the equatorial, middle-, and high-latitude ionosphere was studied. Comparisons of the ray trajectories, integral attenuation, deviations of the projection of radio wave trajectories onto the Earth’s surface from the great-circle arc, and the behavior of the angle between the wave phase and wave energy directions, as well as the angle between the direction of propagation and the external magnetic field obtained for quiet and disturbed conditions, have been performed. We consider a geomagnetic storm that occurred in 2011, with the main storm phase occurring on September 26, and the day after geomagnetic disturbances, September 29, as disturbed conditions in the ionosphere.     

Aluminum and germanium paramagnetic centers in vein quartz and rock crystals from the Subpolar Urals

The major economic types of vein quartz and rock crystals from the Subpolar Urals were studied using electron paramagnetic resonance. Quartz is characterized by widely variable concentrations of aluminum and germanium paramagnetic centers. The average values and ranges of these concentrations increase from older to younger generations of quartz. The lowest content of aluminum and germanium paramagnetic centers is typical of granulated and primary fine-grained quartz; in coarse-grained quartz and rock crystals, the content is much higher. According to the data obtained, granulated and primary fine-grained quartz should be regarded as a potentially high-quality raw material for glass melting, because these quartz varieties are distinguished by the lowest contents of alien structural centers. Once mineral impurities eliminated, high-quality quartz concentrate can be produced from this quartz.     

Ion drift in the earth’s inner plasmasphere during magnetospheric disturbances and proton temperature dynamics

Based on the thermal plasma measurements in the Earth’s inner plasmasphere on the INTER-BALL-2 and MAGION-5 satellites it has been indicated that the plasmaspheric ion temperature as a rule decreases during the main phase of magnetic storms; in this case the plasma density increases or remains at the level typical of undisturbed conditions. The physical mechanism by which the ion drift during a magnetic storm results in a temperature decrease is described. It is shown that the third adiabatic invariant also remains in processes with a characteristic time shorter than the period of charged particle drift around the Earth for cold equatorial plasma. The constructed model of the drift shell displacement from the Earth caused by a decrease in the magnetic field in the inner magnetosphere during the development of a magnetic storm satisfactorily describes the decrease in the proton temperature near the equatorial plane.     

Provenance and source rocks of Riphean sandstones in the Uchur-Maya region (east Siberia): Implications of geochemical data and Sm-Nd isotopic systematics

As is shown based on geochemical data and Sm-Nd isotopic systematics, accumulation of sandy deposits in the Riphean protoplatform cover of the Southeast Siberian platform was controlled by influx of primary and recycled sedimentary material derived from magmatic and metamorphic complexes of the eastern Aldan shield in the course of denudation of the Early Proterozoic accretionary orogen formed prior to 1.9 Ga. First indications of endogenic material influx into sedimentary basins are established in the Totta Formation of the Middle Riphean. They mean contribution to sedimentation of material weathered and eroded from external recycled orogens and synsedimentary volcanics that marked commencement of rifting in the platform marginal zone. Provenances of this material were situated most likely to the east and southeast off the Yudoma-Maya trough.     

Observations of large-scale plasma convection in the magnetosphere with respect to the geomagnetic activity level

The data of the ionospheric observations (the daily f plots) at the Yakutsk meridional chain of ionosondes (Yakutsk–Zhigansk–Batagai–Tixie Bay) with sharp decreases (breaks) in the critical frequency of the regular ionospheric F2 layer (foF2) are considered. The data for 1968–1983 were analyzed, and the statistics of the foF2 break observations, which indicate that these breaks are mainly registered in equinoctial months and in afternoon and evening hours under moderately disturbed geomagnetic conditions, are presented. Calculations performed using the prognostic model of the high-latitude ionosphere indicate that the critical frequency break position coincides with the equatorial boundary of large-scale plasma convection in the dusk MLT sector.     

Niobium in hydrothermal systems related to alkali granites: Thermodynamic description of hydroxo and hydroxofluoride complexes

Available experimental data on the solubility of Nb₂O₅ and the stability constants for particles of an aqueous solution in the Nb–O–H–F system were processed. As a result, a set of thermodynamic properties for 25°C and 1 bar was obtained, in addition to the equation parameters for the HKF model (Helgeson–Kirkham–Flowers) for hydroxo and hydroxofluoride niobium complexes. F^– ion is the most important factor governing the concentration of dissolved Nb: neutral hydroxo complex Nb(OH)₅(aq) is formed at a low HF concentration, whereas an increase in HF results in an increase in the first Nb(OH)₄F(aq) and second Nb(OH)₃F₂(aq) fluoride complexes. The Nb(OH)₅F^– oxofluoride anion determines oxide solubility in alkali F-bearing fluids. Neutralization of acidic fluoride solution can be the main factor leading to niobium deposition.