Вестник Кольского научного центра РАН. 2010, №2.

contents PHYSICS OF HIGH LATITUDE Yu.V. Balabin, E.V. Vashenyuk, B.B. Gvozdevsky SOLAR COSMIC RAY DYNAMICS BY GROUND-LEVEL MEASUREMENTS The new technique of the inverse problem solution - restoration of parameters of primary solar cosmic rays (SCR) BY the data of the ground based neutron monitors network has been created. The technique uses methods of optimization and modern magnetosphere models. The errors related to exact calculations of geomagnetic thresholds are eliminated. Using this technique over 30 events have been investigated. Two components differing by the form of spectrum and conditions of interplanetary propagation have been found in most cases. Possible mechanisms of their generation in the Sun are considered. Keywords: neutron monitor, generation, primary cosmic rays flux spectrum, ground enhancement, relativistic protons, magnetosphere models. T.A. Yahnina, A.G. Yahnin RELATIONSHIP BETWEEN SUB-OVAL PROTON AURORAS AND GEOMAGNETIC PULSATIONS IN THE PC1 RANGE (REVIEW) Recent results of the relationship between different forms of sub-oval proton auroras and geomagnetic pulsations in the Pc1 range (0.2-5 Hz) are reviewed. As known, pulsations of the Pc1 range are indicators of electromagnetic ion-cyclotron (EMIC) waves. It is shown that each type of the proton aurora observed from the IMAGE spacecraft associates with a specific kind of geomagnetic pulsations as observed at ground stations conjugated with the proton aurora. It is concluded that sub-oval proton auroras map into the magnetospheric domains where ion-cyclotron instability develops. The instability leads to both the EMIC wave generation and scattering protons into the loss cone. Variety of proton aurora forms and related geomagnetic pulsations is due to different ion-cyclotron interaction regime depending on configuration and dynamics of the cold and hot plasma regions in the near-Earth magnetosphere under different geophysical conditions. Keywords: geomagnetic pulsations, proton auroras, ion-cyclotron instability. V.S. Mingalev, G.I. Mingaleva MATHEMATICAL MODELS OF THE BEHAVIOR OF IONOSPHERIC D-, E- AND F-LAYERS DEVELOPED IN THE POLAR GEOPHYSICAL INSTITUTE DURING ITS 50-YEARS HISTORY A review of mathematical models of the Earth’s ionosphere, developed in the Polar Geophysical Institute during the period of its existence, is presented. Theoretical papers, including the physical and mathematical formulations of the problems, are reviewed which deal with the study of the physical and chemical processes in D, E, and F regions of the Earth’s ionosphere. The one-, two-, three-dimensional, and global mathematical models of the terrestrial ionosphere are reviewed. Keywords: Polar Geophysical Institute, terrestrial ionosphere, mathematical modeling. V.V. Pchelkin, M.I. Beloglazov, A.N. Vasiljev, A.I. Voronin METHODOLOGICAL ASPECTS OF ESTIMATING Q-FACTOR OF THE EARTH-IONOSPHERE CAVITY BASED ON FOURIER ANALYSIS. EVALUATION OF RESONATOR CHARACTERISTICS BY Q-TYPE ELF BURSTS Methodological aspects of estimating the Earth-ionosphere cavity properties with application of Fourier analysis are considered. It is shown that the problem of both non-unique choice of the function approximating the spectrum of the function and accounting for the background, as well as possible irregularity of the spectrum can lead to a significant difference in the estimates of resonator Q-factor. The technique is proposed of estimation of circuit Q-factor by the study of Q-tipe ELF bursts. The essence of the technique consists in imposing of the normalized Q- type bursts and determining by the shape of amplitude quasi-exponential decrease of the damping rate and Q-factor. The values of the Q-factor obtained by this technique are compared with those calculated by other techniques, as well as with the estimates known from the literature. The performed testing of the proposed technique for the chosen time interval yielded the value of ~3.6, while the estimated based on the Fourier transform of the data for the same time interval gave the estimates of the Q-factor in the range from 3.3 to 4.3 (the scattering stems from non-uniqueness of the approximation of the spectrum and possibly by its irregular character). It is demonstrated that the Q-type bursts allow estimating the first Schumann resonance frequency, however the accuracy of such estimates is lower than the accuracy of the estimates obtained with Fourier transform application. Keywords: methodical aspects, resonator Earth-Ionosphere, Fourier analysis, merit factor of the resonator, Q-type bursts, factor of attenuation, first Schumann resonance. 110