A contribution to the theory of the equatorial noise generation in the Earth’s magnetosphere

This work is devoted to the study of the generation of the equatorial noise—electromagnetic emission below the LHR frequency observed near the equatorial plane of the magnetosphere at distances of ~4R_E. According to accepted views, the generation of the equatorial noise is related to the instability of ring current protons. In this work, a logarithmic distribution of energetic protons over the magnetic moment with an empty loss cone is proposed, and arguments for the formation of such a distribution are presented. The main result of the work is the calculation and analysis of the instability growth rate of waves forming the equatorial noise. The growth rate obtained in this work significantly differs from that encountered in the literature.     

Whistler Growth Rates in the Magnetosphere According to Measurements of Energetic Electron Fluxes on the Van Allen Probe A Satellite

Geomagnetism and Aeronomy - Measurements of the differential fluxes of energetic electrons in the equatorial region of the magnetosphere in the energy range from units of keV to hundreds of keV...     

Studying the Volga R. in the voyage of the R/V Akademik Topchiev

The expedition for studying the Volga R. was organized by the Institute of Oceanology, Russian Academy of Sciences and the Institute of Inland Water Biology, Russian Academy of Sciences, with the participation of the Institute of Geochemistry and Analytical Chemistry on the r/v Akademik Topchiev (June 2–18, 2016). The main objective of the expedition studies of the Institute of Oceanology, Russian Academy of Sciences, was to examine the sedimentation and biogeochemical processes in the mixing zone of the Volga and its tributaries with the aim to assess the present-day water quality and trends in its changes in the recent years. In this context, the study was focused on the aerosols of near-water layer, surface water, and bottom sediments along the route the Rybinsk Reservoir (Borok Settl.)–Lower Volga (Astrakhan C.). The methodology was based on a multidisciplinary study of dissolved compounds and suspended particles (<1 μm). The main attention was focused on studying the spatial variations of biogenic substances, organic compounds (Corg in suspension and solution), the suspension itself, and hydrcarbons.     

Proton interaction with quasi-electrostatic whistler mode waves in an inhomogeneous plasma (magnetosphere)

We study the interaction between energetic protons of the Earth’s radiation belts and quasi-electrostatic whistler mode waves. The nature of these waves is well known: whistler waves, which are excited in the magnetosphere due to cyclotron instability, enter the resonant regime of propagation and become quasielectrostatic, while their amplitude significantly increases. Far enough from the equator where proton gyrofrequency and transversal velocity increase the nonlinear interaction between these waves and energetic protons becomes possible. We show that plasma inhomogeneity may destroy cyclotron resonance between wave and proton on the time scale of the order of particle gyroperiod which in fact means the absence of cyclotron resonance; nevertheless, the interaction between waves and energetic particles remains nonlinear. In this case, particle dynamics in the phase space has the character of diffusion; however, the diffusion coefficients are determined by the averaged amplitude of the wave field, but not by its resonant harmonics. For real parameters of the waves and magnetospheric plasma, proton pitch-angle diffusion leading to their precipitation from the magnetosphere becomes essential.     

Simultaneous Observations of EMIC Waves,ELF/VLF Waves,and Energetic Particle Precipitation during Multiple Compressions of the Magnetosphere

Geomagnetism and Aeronomy - Simultaneous observations of ELF/VLF and EMIC waves from Van Allen Probe satellites in the daytime Earth’s magnetosphere and on the ground during multiple...     

Auroral pulsations and accompanying VLF emissions

Results of simultaneous TV observations of pulsating auroral patches and ELF-VLF-emissions in the morning sector carried out in Sodankylä (Finland) on February 15, 1991 are presented. Auroral pulsating activity was typical having pulsating patches with characteristic periods of about 7 s. Narrow-band hiss emissions and chorus elements at intervals of 0.3–0.4 s formed the main ELF-VLF activity in the frequency range 1.0–2.5 kHz at the same time. The analysis of auroral images with time resolution of 0.04 s allowed perfectly separate analysis of spatial and temporal variations in the auroral luminosity. Mutual correspondence between the behaviour of the luminous auroral patches and the appearance of ELF noise type hiss emissions and VLF chorus trains was found in two intervals chosen for analysis. While the hiss emissions were associated with the appearance of luminosity inside a limited area close to the zenith, the structured VLF emissions were accompanied by rapid motion of luminosity inside the area. The spatial dimension of the pulsating area was about 45–50 km and luminosity propagated inside it with velocity of about 10–12 kms. We discuss a new approach to explain the 5–15 s auroral pulsation based on the theory of flowing cyclotron maser and relaxation characteristics of ionosphere.     

Analysis of the influence that climatic variability has on the formation of the total-ozone-content field at extratropical latitudes of the Northern Hemisphere

Having applied the method of discriminant analysis to the TOMS data of satellite sounding of the total ozone content (TOC) in the March months of 1979–2008, the authors could make a new estimate of the TOC field variability in the Northern Hemisphere and interlongitudinal regularities of its changes under the action of climatic variability. The effects of temperature variations in the polar stratosphere, El Niño, and quasi-biennial oscillation (QBO) have proven comparable and reach 80 DU in some regions. The influence of the Arctic Oscillation (AO) reaches 40 DU. The regions of TOC variations and their location and dimensions change depending on the phases of QBO, AO, and El Niño-Southern Oscillation (ENSO). Three regions of increased TOC—over Europe, Eastern Siberia, and the Pacific Ocean—are formed in years with a warm stratosphere. A compensating TOC decrease takes place in the tropics and over Greenland. In the years of El Niño and the easterly QBO phase, the TOC increases over Europe and drops over the central Pacific, as well as to the south from 45° N. The AO controls the ozone growth over most of Eurasia at temperate latitudes and its weak drop over the Atlantic. It was impossible to obtain such quantitative estimates with the use of methods based on an independent analysis of the TOC series at individual points of the coordinate grid. Testing with the Monte Carlo method confirmed that the results obtained are significant with a probability of 95–99.9%.     

Comparative Analysis of Models for Disintegration of Meteoric Bodies

A model for fast sequential disintegration of meteoroids in the terrestrial atmosphere, which takes a scale factor into account, was published by Ivanov and Ryzhanskii (1997). The trajectory of a nonablating body was determined by stage-by-stage computations; the number of stages could be more than 30. In the present study, this physical model is represented by a set of differential equations, which are solved by the method of separation of variables, in particular, with allowance for ablation. For bounded values of the mass-loss parameter, the solution is expressed in terms of elementary functions. Examples of the calculation of meteoric-body trajectories based on other models and their comparison with the proposed model are presented. Comparison of the results indicate the efficiency of these models in solving the inverse problems of dynamics and disruption of meteoroids in the atmosphere.