Quasitrapped protons (E p =1–11 MeV) nearL=4 registered by intercosmos-13 satellite

Summary Data obtained from apparatus detecting energetic particles on low altitude polar orbiting satellite Intercosmos-13 show enhancement of quiasitrapped proton flux (E_p=1–11 MeV) near L=4 in comparison with both and lower L. This phenomenon persists during intervals with low level of geomagnetic activity. Possibility of influence of false pulses on the result is discussed.     

On the resolving power of the VLF method

In the paper, the mathematical tools, used for the modelling of the electromagnetic field of the harmonic plane wave in the two-dimensional inhomogeneous medium (the case ofE-polarization), are presented. Further, the resolving power of some parameters, that are measured in the VLF and VLF-R methods, is compared in the case of two vertical conductive dykes. To this aim, all the usual parameters of the VLF method and the most important parameter of the VLF-R method () have been chosen. Two groups of models that differ in resistivities have been considered. In each of the groups the distance of the dykes is variable. The parameters |H _y|, which has shown most promising in this respect, is examined also from the point of view of the sensibility to geological noise. The results of the modelling are illustrated by two examples of the results of field measurements.     

Expansion of geoid heights into a spherical harmonic series

Summary An algorithm is derived to compute the coefficients of a spherical harmonic series for the geoid radius vector that are a solution to a system of linear equations, containing Stokes' constants of the geopotential.     

Polarization characteristics of ulf electromagnetic waves in an inhomogeneous anisotropic ionosphere of the Earth

Summary Drawing on [6], the height profiles of local complex polarization and local polarization characteristics of electromagnetic waves in several models of the Earth's ionosphere are analysed. The profiles were obtained with the aid of a computer program for modelling propagating [5]. The analysis was carried out a) for a flxed given configuration of the external magnetic field of the EarthB ₀ at a number of discrete frequencies f<5 Hz, b) for chosen model of the ionosphere at a fixed given frequency f=1 Hz and in connection with a change of the dip of the lines of force and of the magnitude of the external (homogeneous) magnetic field|B ₀|, c) for various models at f=1 Hz and a varying configuration of the external magnetic field, reflecting the change in geomagnetic latitude. The results of the analysis will serve as an aid to the interpretation of the results of solving the problem of wave propagation through the ionosphere.     

Frequency-time analysis of geomagnetic beating-type pulsationsPc3

Summary The mechanism of beating of Pc3 type pulsations is studied. Using the method of numerical computation of a sonagram (the method of frequency-time analysis) a set of samples of pulsations from the Budkov Observatory is treated (1968–1969) mostly at K-indices equal to 2–3. By comparing f–t diagrams with the spectra of the samples an attempt has been made at interpreting the beating as a superposition of the frequency components, contained in the pulsation signal. In most observed cases it is possible to determine two close frequencies, the difference of which is on the average =5.4 mHz. The average carrier frequency of the samples was =37.6 mHz, and the average frequency of the beating =2.7 mHz. The interval of observed values of f_B amounted to 1–5 mHz. A tendency was observed for f_B to increase with increasing degree of disturbance of the geomagnetic field.     

Some mechanical analogies of magnetodynamic oscillations in a homogeneous medium

Zusammenfassung Es wird auf die Analogien hingewiesen zwischen dem einfachsten Fall der Resonanz einer ebenen MD-Welle im Modell homogener Schicht der Erdmagnetosph?re und horizontaler Schwingung einer homogenen elastischen S?ule mit einem befestigten Ende. Es wird qualitativ die Analogie zwischen dem Anprall eines materiellen K?rpers an eine elastische S?ule mit einem befestigten Ende und dem Stoss der Front von Sonnenwind auf die Erdmagnetosph?re angedeutet. Diese Ann?herung erm?glicht die Illustration einiger Züge von Pulsationen, welche pl?tzliche Ver?nderungen in magnetischem Felde der Erde (Impulse si, ssc u. ?.) begleiten und deren Beschreibung auf Grund pr?ziser Theorie der Verbreitung von MD-Wellen sehr schwierig ist.

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