HF ducting control due to modification of the ionosphere by powerful radiation

The conditions are experimentally investigated for ionospheric duct excitation due to radio wave refraction on the electron density gradient as well as for the escape of the waveguide modes to the Earth at the expense of the radio wave aspect scattering on artificial ionospheric turbulence. The geophysical conditions for effective HF ducting control are determined. The temporal and frequency characteristics of the escaping mode are evaluated.Mari Polytechnic Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 36, No. 5, pp. 390–397, May, 1993.     

Variations in the parameters of scattered signals and the ionosphere connected with plasma modification by high-power radio waves

We describe the results of using the incoherent scatter technique to observe time-altitude variations in regular parameters of the ionospheric plasma and wave disturbances, which accompanied periodic modification of the near-Earth plasma by radio waves emitted by the “Sura” facility. A distinctive feature of the experiments was that the processes in the ionosphere were diagnosed at a distance of about 1000 km from the facility. It was found that the spectrum composition of wave disturbances in the electron density was changing noticeably during the active experiment. Quasi-periodic processes in the ionosphere were observed with a delay of about 40–60 min. The relative amplitude of wave disturbances was equal to 0.02–0.10, and the periods were equal to 30, 60, 120, and 150–180 min. The observed effect can be explained by the generation and/or amplification of traveling ionospheric disturbances. The results of theoretical estimations agree well with the observational data.     

On the effects observed during modification of the earth’s upper ionosphere by high-power short radio pulses

We report on the results of studies of the evolution of artificial ionospheric turbulence (AIT) excited by short pulses of high-power short-wave O-mode radio emission in the ionospheric F region. On the basis of the obtained experimental data, it is assumed that the streams of thermal and suprathermal electrons generated in the regions of resonant interaction between a high-power radio wave and the plasma and propagating along the geomagnetic field stimulate the development of plasma perturbations far away from the primary-turbulence regions. Specific features of the measurement procedure are considered, an empirical model of the observed phenomena is developed, and possible problems in the further studies are outlined. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 8, pp. 643–663, August 2006.     

The orbit space of the action of gauge transformation group on connections

The behaviour of orbits of the action of the group of smooth gauge transformations on connections for a principal bundle P(M, G) is discussed with and without compactness assumption on M and G. In the case of compact M and with suitable conditions on G a stratification structure for the space of orbits is established. A natural tame weak Riemannian metric is given on each stratum.     

Fluxes of GCR and SCR iron nuclei in the international space station orbit

The anticipated flux of iron nuclei and ions in the energy interval 26–168 MeV/nucleon in the orbit of the international space station (ISS) during the exposure of the PLATAN-M dielectric track detector from January 26, 2002, to August 3, 2004, has been estimated. The calculation is based on the data obtained using the SIS spectrometer onboard the ACE space station and the last version of the model describing the penetration of charged particles into the Earth’s magnetosphere. The time variations in the GCR iron nuclei intensity in the ISS orbit during solar cycle 23 have been obtained using the data of the PLATAN-4 and PLATAN-5 earlier experiments onboard the Mir space station.     

Suppression of chaotic oscillations in a microchip laser by injection of a new orbit into the chaotic attractor

Suppression of chaotic instability arising in a Nd:YVO(4) microchip laser subject to frequency-shifted optical feedback is accomplished by injection of one of the periodic orbits into the bifurcation region of another chaotic system driven by pump modulation. Various periodic patterns, which do not exist in the original chaotic attractor, can be extracted from the chaotic oscillation by use of this nonfeedback chaos-control technique.     

Scattering of electromagnetic waves by traveling-wave structures in the ionosphere

The diffraction of electromagnetic waves, incident obliquely on an ionospheric layer with density inhomogeneities of the traveling-wave type, is investigated by S. M. Rytov's method of smooth perturbations. The spatial dependencies of the properties of the ionosphere and of the wavelike inhomogeneities are taken into consideration. The diffraction patterns are analyzed for several variants of height profiles of the wave perturbations. The solutions obtained make it possible to estimate the effect of the form of ionospheric profile and the distribution of the level of disturbance of the wavelike inhomogeneities with respect to altitude on the diffraction effects.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 21, No. 12, pp. 1717–1727, December, 1978.The author expresses his appreciation to V. N. Krasil'nikov for attention and advice.     

"火星快车"下视雷达对火星电离层探测简介

火星是近年来深空探测的热点,对火星电离层的观测和研究是火星探测的主要内容之一.欧洲航天局2003年发射了火星探测器"火星快车",它所搭载的下视雷达MARSIS(火星地表和电离层探测雷达)为火星电离层探测提供了大量数据,文章简单介绍了利用MARSIS探测火星电离层的基本原理,探测数据的结构和利用这些探测数据进行电离层研究的现状.     

Analysis of Coleman-Weinberg potentials in orbit space: General method and application to the inflationary universe

We present a general method to analyze Colemann-Weinberg potentials in the orbit space, which is applicable to any irreducible representation. As an example, the structure of the SU(5) Coleman-Weinberg potential with scalars asigned to the adjoint representation is analyzed in complete detail, which confirms the general conclusion reached by Breit, Gupta and Zaks, and Moss that the phase transition in the new inflationary scenario of the early universe is problematic. We show that the disease found in the SU(5) case is common to all SU(N) (N > 3) and SO(2 N) (N ≠ 4,8) adjoints, and that the adjoints of SO(8) and exceptional groups are immune from the 1 disease.