Character of turbulence in the boundary regions of the Earth’s magnetosphere

The statistical features of the magnetic field and ion flux fluctuations in the boundary regions of the Earth’s magnetosphere have been studied on different timescales based on the Interball satellite measurements. Changes in the form and parameters of the probability density function have been studied for the periods when the satellite was in the solar wind plasma, different magnetosheath regions, and the turbulent boundary layer (TBL) at the polar cusp outer boundary. Variations in the probability density function maximum (P ₀) and the kurtosis value as characteristics of the turbulence property evolution on different timescales have been studied. Two asymptotic regimes of P ₀, which are characterized by different power laws, have been found. The structural functions of different orders and the types of diffusion processes in different regions, depending on time variations in the generalized diffusion coefficient, have been studied in order to analyze the character of diffusion processes. For the magnetosheath regions, TBL, and polar cusp, it has been found that the diffusion coefficient increases in the course of time (i.e., the regime of superdiffusion has been obtained). In the foreshock region before the main shock, turbulent processes are described by the Kolmogorov model of classical diffusion.     

Seismotectonic destruction of the Earth’s crust in the zone of interaction of the northeastern side of the Baikal rift and the Aldan-Stanovoy block

The paper presents the modern structural-tectonic pattern and a tectonodynamic model of the zone of interaction of the most seismically active northeastern side of the Baikal rift zone (BRZ) and the conjugate system of seismogenic structures of the Aldan-Stanovoy block, where disastrous events with M ≥ 6.0 have been reported. Regularities in the structural formation of active faults and their kinematics are discussed. The faults form block structures accumulating significant tectonic strain. Motions between large tectonic blocks cause sudden release of the strain, which results in catastrophic events (M ≥ 6.0) with focal mechanisms of definite kinematic type.     

Seismic Studies of the Earth’s Core

Izvestiya, Physics of the Solid Earth - Abstract—The paper presents the review of the conceptually most important results of seismological studies of the Earth’s core and their...     

Nonzonal structure of the response of the global field of the Earth’s atmospheric temperature to solar activity

The work describes the results of calculations obtained with the Atmospheric Research Model (ARM) general circulation model. The temperature response of the troposphere and middle atmosphere to variations in UV solar radiation were found to have a large-scale wave structure when planetary waves at the lower model boundary were taken into account. In the present paper, the results from the processing of global temperature fields with three databases (ERA-20C, NOAA-CIRES 20th Century Reanalysis, v2, and NCEP/NCAR Reanalysis I) are provided. Analysis of the differences of the mean monthly temperature global fields (January and July) between the maxima and minima of three solar activity cycles (21, 22, and 23 cycles) also demonstrated their nonzonal structure. It was shown that the amplitude of this difference in January in the stratosphere (10 hPa) can be 7–29 K in the Northern Hemisphere. In July, this effect is prominent in Southern Hemisphere. In the troposphere (500 hPa), a nonzonal temperature effect is present in both the Northern and Southern Hemispheres; the amplitude of the effects amounts to approximately 5–12 K. In conclusion, we discuss that the mechanism of solar energy impact on atmospheric temperature discovered by numerical modeling is supported after reanalysis data processing.     

Models of the Earth’s plasmapause position

正The plasmasphere is a region of relatively dense(~10–10000 cm~(–3))plasma,surrounding the Earth and extending to distances of about five Earth radii(R_E).It is filled with large amount of cold(~1 e V)plasma originated from the Earth’s ionosphere and co-rotating with the Earth due to the large scale co-rotation electric field.The outermost     

Estimation of the temperature in the Earth’s interior from surface measurements of the electromagnetic field

The possibility of contactless remote estimation of the temperature in the Earth’s interior from surface magnetotelluric (MT) measurements is examined. The neuronet analysis of MT and temperature measurements in the Bishkek geodynamic research area (the Northern Tien Shan) showed that a contactless electromagnetic geothermometer can in principle be realized. An optimal method including MT measurements and treatment of available thermograms is developed. The method minimizes uncertainties of the remote temperature estimation. The use of six to eight thermograms for calibration of electromagnetic data is shown to provide a 12% relative error of prediction, and a priori geological information available for the region under study can reduce this error. Areas of practical application of a contactless electromagnetic geothermometer are outlined.     

Constraining the focal mechanism of the Lushan earthquake with observations of the Earth’s free oscillations

The amplitudes of the Earth's free oscillations have a close relationship to earthquake focal mechanisms. Focal mechanisms of large earthquakes can be well analyzed and constrained with observations of long period free oscillations. Although the 2013 Lushan earthquake was only moderately sized, observable spherical normal modes were excited and clearly observed by a superconductive gravimeter and a broadband seismometer. We compare observed free oscillations with synthetic normal modes corresponding to four different focal mechanisms for the Lushan earthquake. The results show that source parameters can be analyzed and constrained by spherical normal modes in a 2.3–5 mHz frequency band. The scalar seismic moment M0 has a major influence on the amplitudes of free oscillations; additionally, the strike, dip, rake and depth of the hypocenter have minor influences. We found that the synthetic modes corresponding to the focal mechanism determined by the Global Centroid Moment Tensor show agreement to the observed modes, suggesting that earthquake magnitudes predicted in this way can readily reflect the total energy released by the earthquake. The scalar seismic moment obtained by far-field body wave inversion is significantly underestimated. Focal mechanism solutions can be improved by joint inversion of far- and near-field data.     

On the relation of variations in the travel times of seismic waves with the changes in the speed of the Earth’s rotation

The results of long-term sounding of the lithosphere by seismic waves from the deep-focus Hindu Kush earthquakes are presented. The travel time series of the first longitudinal wave on a fixed base are constructed for six seismic observation stations (SS) located on the Russian Platform (the Obninsk SS), on the Siberian Platform (the Eltsovka SS), on the Cis-Ural Trough (the Arti SS), in the Central-Ural Megazone (the Sverdlovsk SS), in the Transbaikalia (the Bodaibo SS), and in the Northern Tien Shan (the Przhevalsk SS). The time series duration in years for these stations ranged from 1964–1970 to 2007. The travel time series of seismic waves for the stations indicated are characterized by multi-slope negative linear trends caused by changes in the stress-strain state of rocks. From the comparison of the trend slopes at different stations it follows that the changes in the stress conditions within the lithosphere are relatively weak in the aseismic regions of the Russian and Siberian Platforms and in the Ural Megazone, whereas in the seismically active regions of Tien Shan, Transbaikalia and the Cis-Ural Trough they are more pronounced. The correlation has been observed between the time series trends of the average annual travel times of seismic waves and the time series of the Earth’s rotation speed. The strongest correlation between the series can be seen for the stations, located on the platforms with weak manifestations of both seismicity and active geodynamic processes. Within the long-term periods of deceleration and acceleration of the Earth’s rotation, travel times of seismic waves are decreased and increased, respectively.     

On the gradient of curvature of the plumblines of the Earth’s normal gravity field and its isocurvature lines

This paper presents an approach to determine the gradient of curvature of the normal plumblines at a point P above the ellipsoid and introduces a new geometrical object which is the isocurvature line. The assumed facts are the coordinates of the point P and the formula for the normal gravity potential U. For the determination of the gradient of the normal plumbline curvature k at the point P we define a small circle on the meridian plane of P whose center is at the point P. The circle has the radius of one meter and interior D. In this circle we construct a curvature replacement function to approximate the curvature function k. This replacement function is a quotient of polynomials hence it is easy to find its partial derivatives at the point P. For the construction of replacement function we make the assumption that in the interior of the circle D the first order partial derivatives of U behave linearly and the second order partial derivatives have constant values which equal their value at the point P. Then we set the gradient of the curvature function to be equal with the gradient of the aforementioned replacement function at P. An isocurvature line of the normal gravity field passing through a point P is a curve such that the value of the function of the plumblines’ curvature k is constant and equals k(P). We give a formula to find the direction of the isocurvature line on the meridian plane and we prove that there are infinitely many isocurvature lines passing through the point P and they all lie on a special surface, the isocurvature surface.     

Manifestation of solar and geodynamic activity in the dynamics of the Earth’s rotation

The relationships between different manifestations of solar and geomagnetic activity and the structural peculiarities of the dynamics of the pole wobble and irregularities in the Earth??s rotation are studied using singular spectrum analysis. There are two close major peaks and several lower ones in the same frequency range (1.1?C1.3 years) in the Chandler wobble (CW) spectrum. Components in the geomagnetic activity were distinguished in the same frequency band (by the Dst and Ap indices). Six- to seven-year oscillations in the Earth??s rotation rate with a complex dynamics of amplitude variations are shown in variations in geomagnetic activity. It is revealed that secular (decade) variations in the Earth??s rotation rate on average repeat global variations in the secular trend of the Earth??s geomagnetic field with a delay of eight years during the whole observation period.     

Electrification of Dielectric Satellites under the Influence of Electron Flows of the Earth’s Radiation Belts

Geomagnetism and Aeronomy - The effect of electron fluxes from the Earth’s radiation belts on satellites made of dielectric materials is studied theoretically. Spherical shaped nanosatellites...     

Experience of Modeling the Seismotectonic Flow of the Earth’s Crust in Central Asia

Izvestiya, Physics of the Solid Earth - Abstract—Tectonic flow of crustal rock masses (a creep flow) in Central Asia is numerically modeled using the Stokes equations within a region limited...     

Distribution relations of tectonical stresses in the upper part of the Earth’s crust

Due to an analysis of the data in the literature on stress measurements in mining sites in the former Soviet Union, including those performed in the mines of the Kola Peninsula and the Kola Superdeep Borehole SG-3, the subhorizontal tectonic stresses were reported to exceed the lithostatic stresses. As a rule, tectonic stresses are attributed to the interaction boundaries of blocks of different sizes: from lithosphere platforms to blocks of IV–V ranks.     

Influence of the atmospheric surface layer on the penetration of the electric field from the earth’s surface into the ionosphere

In the used model, the quasistationary electric field in the atmosphere of the Earth is obtained by solving the conductivity equation. The penetration characteristics of the electric field from the Earth’s surface into the ionosphere depend on both atmospheric and ionosphere conductivity. The ionosphere is taken into account by setting a special condition on the upper boundary of the atmosphere. The influence of the atmospheric surface layer with a reduced conductivity on the penetration of the electric field from the surface of the Earth into the ionosphere is analyzed.     

Determining the thickness of the low-latitude boundary layer in the Earth’s magnetosphere

We describe a method for determining the thickness of the low-latitude boundary layer (LLBL) of the Earth’s magnetosphere at the dayside near the equatorial plane based on the data gathered by a single satellite that traverses the layer and measures the plasma velocity. The method may be applied when the position of the magnetopause and the magnetosheath parameters fluctuate. The necessity of taking the presence of outer and inner LLBL regions into account is analyzed. The developed method is tested using the analysis results of two almost simultaneous close traverses of the magnetopause completed by the THEMIS mission satellites that provided relatively precise data on the LLBL thickness. It is shown that the developed method makes it possible to determine the LLBL thickness with an accuracy of ～10%.     

Analysis of Methods for Estimating the Energy of Sources of Acoustic-Gravity Waves in the Earth’s Atmosphere

Izvestiya, Physics of the Solid Earth - Abstract—A comparative analysis is presented of the approaches and methods for estimating the energy of the sources of acoustic-gravity waves (AGW) in...     

Features in the Behavior of the Solar Wind behind the Bow Shock Front near the Boundary of the Earth’s Magnetosphere

Geomagnetism and Aeronomy - Macroscopic discontinuous structures observed in the solar wind are considered in the framework of magnetic hydrodynamics. The interaction of strong discontinuities is...     

Influence of Oxygen Ions on the Structure of the Thin Current Sheet in the Earth’s Magnetotail

Geomagnetism and Aeronomy - During geomagnetic substorms, the current sheet in the Earth’s magnetotail can transversely reduce in thickness from a few radii of the Earth (RE) to one to...     

Environmental-geochemical state of the Yuzhnoural’skaya SDPP reservoir

The presented results were obtained in a long-term multidisciplinary study of the water-cooling reservoir of the Yuzhnoural’skaya SDPP, burning high-ash brown coals from the Chelyabinsk Basin. Up-to-date analytical methods (X-ray fluorescence analysis on synchrotron beams, atomic absorption spectrometry, and capillary electrophoresis) were used to study the microelement composition of coal, ash, and slag of the Yuzhnoural’skaya SDPP, soils from ash dumps and territories adjacent to the SDPP, as well as reservoir bottom sediments. The hydrochemical characteristics of the reservoir and water chemistry in the SDPP engineering system were determined. The levels of accumulation of microelements and heavy metals by aquatic organisms in the reservoir were evaluated. Special attention is paid to the analysis of the sources of arsenic in the reservoir.